<PAGE>
 
                    U.S. SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549


                                   FORM 10-Q
 
(Mark One)
[X]    QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
 EXCHANGE ACT OF 1934

                 For the quarterly period ended March 31, 1998
 
[_]    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES
 EXCHANGE ACT OF 1934

          For the transition period from ____________ to ____________

                        Commission file number: 1-9083
                                        
                             POLYPHASE CORPORATION
            (Exact name of registrant as specified in its charter)

          NEVADA                                             23-2708876
(State or other jurisdiction of                            (I.R.S. Employer
incorporation or organization)                             Identification No.)


                            4800 BROADWAY, SUITE A
                              DALLAS, TEXAS 75248
                   (Address of principal executive offices)

                                (972) 386-0101
             (Registrants's telephone number, including area code)


Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15 (d) of the Exchange Act during the past 12
months ( or for such shorter period the registrant was required to file such
reports), and (2) has been subject to such filing requirements for the past 90
days.
Yes    X        No 
    -------        -------          

Indicate the number of shares outstanding of each of the issuer's classes of
common stock, as of the latest practicable date.

Common Stock, $.01 par value                           14,672,464
                                              --------------------------
                                              Outstanding at May 8, 1998
<PAGE>
 
                             POLYPHASE CORPORATION
                                   FORM 10-Q
                          QUARTER ENDED MARCH 31, 1998

--------------------------------------------------------------------------------


                               TABLE OF CONTENTS
                               -----------------

PART I. FINANCIAL INFORMATION                                     Page No.
                                                                  --------
 
Item 1. Financial Statements
 
Consolidated Condensed Balance Sheets as of
  March 31, 1998 and September 30, 1997                                2
 
Consolidated Condensed Statements of
  Operations for the Three Months Ended
  March 31, 1998 and 1997                                              4
 
Consolidated Condensed Statements of
  Operations for the Six Months Ended
  March 31, 1998 and 1997                                              5
 
Consolidated Condensed Statements of
  Cash Flows for the Six Months Ended
  March 31, 1998 and 1997                                              7
 
Notes to Consolidated Condensed Financial Statements                  10
 
Item 2. Management's Discussion and Analysis of
  Financial Condition and Results of Operations                       15
 
Item 3. Quantitative and Qualitative Disclosures about Market Risk    16
 
PART II - OTHER INFORMATION
 
Item 1.  Legal Proceedings                                            17
 
Item 6.  Exhibits and Reports on Form 8-K                             17
 
Signature Page                                                        18

                                      -1-
<PAGE>
 
                    POLYPHASE CORPORATION AND SUBSIDIARIES
                     CONSOLIDATED CONDENSED BALANCE SHEETS
                                  (UNAUDITED)

<TABLE>
<CAPTION>



                                     ASSETS
                                                                March 31,       September 30,
                                                               -----------      -------------
                                                                  1998              1997
                                                               -----------      -------------
<S>                                                            <C>              <C>
Current assets:
 Cash                                                          $   987,506      $   1,064,259
 Receivables, net of allowance for doubtful accounts
  of $600,330 and $576,192
   Trade accounts                                               12,046,892         11,576,650
   Current portion of sales contracts                            5,198,806          5,770,626
   Notes receivable                                              2,154,175            939,621
 Inventories                                                    29,949,967         23,002,020
 Prepaid expenses and other                                      1,042,445          1,607,644
                                                                -----------      -------------
    Total current assets                                        51,379,791         43,960,820
                                                                -----------      -------------

Property and equipment:
 Land                                                              415,000            765,000
 Buildings and improvements                                      3,482,680          4,660,582
 Machinery, equipment and other                                  9,225,071          8,953,076
                                                               -----------      -------------
                                                                13,122,751         14,378,658
 Less-Accumulated depreciation                                  (6,602,927)        (5,954,554)
                                                               -----------      -------------
                                                                 6,519,824          8,424,104
                                                               -----------      -------------
 
Other assets:
 Noncurrent receivables
   Sales contracts                                               1,826,609          2,027,518
   Related parties, net of allowance of
   $164,563 and $0, respectively                                   350,071            522,597
 Excess of cost over fair value of net assets of businesses
   acquired, net of accumulated amortization of $2,777,098
   and $2,370,455                                               13,821,641         14,228,284
 Other intangible assets                                         3,196,239          1,197,139
 Restricted cash                                                   706,714            717,358
 Other                                                           1,194,618          1,071,629
                                                               -----------      -------------
                                                                21,095,892         19,764,525
                                                               -----------      -------------
 
                                                               $78,995,507      $  72,149,449
                                                               ===========      =============
</TABLE>

                  The accompanying notes are an integral part
                  of these consolidated financial statements.

                                      -2-
<PAGE>
 
                    POLYPHASE CORPORATION AND SUBSIDIARIES
               CONSOLIDATED CONDENSED BALANCE SHEETS (CONTINUED)
                                  (UNAUDITED)

<TABLE>
<CAPTION>



                      LIABILITIES AND STOCKHOLDERS' EQUITY
 
                                                              March 31,         September 30,
                                                            ------------       --------------
                                                                1998                1997
                                                            ------------       --------------
<S>                                                         <C>                <C>
Current liabilities:
 Notes payable                                              $ 11,179,664        $   9,013,099
 Note payable and accrued interest to related party           15,103,506           13,998,916
 Accounts payable                                              9,406,962            7,775,022
 Accrued expenses and other                                    2,347,873            2,251,035
 Current maturities of long-term debt                          6,600,000            5,720,000
                                                            ------------       --------------
    Total current liabilities                                 44,638,005           38,758,072
 
Long term debt, less current maturities                       24,308,334           23,272,280
Reserve for credit guarantees                                    706,714              717,358
                                                            ------------       --------------
    Total liabilities                                         69,653,053           62,747,710
                                                            ------------       --------------
 
Warrants to purchase common stock
 in subsidiary                                                 1,200,000            2,000,000
 
Stockholders' equity:
 Preferred stock, $.01 par value, authorized
   50,000,000 shares, issued and outstanding 
   125,000 and  132,500 shares, respectively                       1,250                1,325
 Common stock, $.01 par value, authorized
   100,000,000 shares, issued and outstanding
   14,672,464 and 13,664,109 shares, respectively                146,725              136,641
 Paid-in capital                                              29,103,186           28,955,695
 Accumulated deficit                                         (20,133,388)         (20,716,603)
 Notes receivable                                               (975,319)            (975,319)
                                                            ------------       --------------
   Total stockholders' equity                                  8,142,454            7,401,739
                                                            ------------       --------------
 
                                                            $ 78,995,507       $   72,149,449
                                                            ------------       --------------
</TABLE>

                  The accompanying notes are an integral part
                  of these consolidated financial statements.

                                      -3-
<PAGE>
 
                     POLYPHASE CORPORATION AND SUBSIDIARIES
                CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS
                                  (Unaudited)

<TABLE> 
<CAPTION> 

    
                                            For the Three Months Ended
                                                    March 31,
                                          ----------------------------
                                              1998           1997
                                          -----------    -------------

<S>                                       <C>            <C> 
Net revenues                              $33,328,696    $  38,409,223

Cost of sales                              26,818,115       32,623,184
                                          -----------    -------------

Gross profit                                6,510,581        5,786,039

Selling, general and administrative
 expenses                                   4,600,107        3,811,186
                                          -----------    -------------

Operating income                            1,910,474        1,974,853
                                          -----------    -------------


Other income (expenses):
 Interest expense                          (2,262,859)      (1,839,932)
 Interest income and other                    134,279         (115,857)
                                          -----------    -------------
 
  Total other income (expenses)            (2,128,580)      (1,955,789)

Income (loss) before income taxes and 
 warrant accretion                           (218,106)          19,064

Income taxes                                     -              41,418
                                          -----------    -------------

                                             (218,106)         (22,354)
Accretion of common stock purchase 
 warrants of subsidiary                           -            109,647
                                          -----------    -------------

Net income (loss)                            (218,106)        (132,001)

Dividends on preferred stock                  (39,375)         (37,500)
                                          -----------    -------------

Net income (loss) attributable to common 
 stockholders                             $  (257,481)   $    (169,501)
                                          -----------    -------------



Basic income (loss) per share             $      (.02)   $        (.01)
                                          ===========    =============

Diluted income (loss) per share           $      (.02)   $        (.01)
                                          ===========    =============
</TABLE> 

                  The accompanying notes are an integral part
                  of these consolidated financial statements.

                                      -4-
<PAGE>
 
                     POLYPHASE CORPORATION AND SUBSIDIARIES
                CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS
                                  (UNAUDITED)

<TABLE> 
<CAPTION> 
                                           For the Six Months Ended 
                                                   March 31,
                                          --------------------------
                                              1998          1997
                                          -----------    -----------
<S>                                       <C>            <C>
Net revenues                              $70,721,013    $74,575,012

Cost of sales                              57,243,275     62,680,099
                                          -----------    -----------

Gross profit                               13,477,738     11,894,913

Selling, general and administrative 
 expenses                                   9,196,593      8,434,856
                                          -----------    -----------

Operating income                            4,281,145      3,460,057
                                          -----------    -----------
 
 
Other income (expenses):
 Interest expense                          (4,112,627)    (3,414,350)
 Interest income and other                    123,329         95,103
 Gain on sale of assets                       987,857            -
                                           -----------    -----------

  Total other income (expenses)            (3,001,441)    (3,319,247)
                                          -----------    -----------


Income before income taxes,
 warrant accretion and extraordinary item   1,279,704        140,810

Income taxes                                      -          120,528
                                          -----------    -----------

                                            1,279,704         20,282
Accretion of common stock purchase
  warrants of subsidiary                          -          219,520
                                          -----------    -----------

Net income (loss) before extraordinary
 item                                       1,279,704       (199,238)

Extraordinary item:
 Early extinguishment of debt                (616,239)           -
                                          -----------    -----------

 Net income (loss)                            663,465       (199,238)

Dividends on preferred stock                  (80,250)       (75,000)
                                          -----------    -----------

Net income (loss) attributable to common
 stockholders                             $   583,215    $  (274,238)
                                          ===========    ===========
</TABLE> 

                  The accompanying notes are an integral part
                  of these consolidated financial statements.

                                      -5-
<PAGE>
 
                     POLYPHASE CORPORATION AND SUBSIDIARIES
          CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS (CONTINUED)
                                  (UNAUDITED)
<TABLE>
<CAPTION>
 
  
                                   For the Six Months Ended
                                           March 31,
                                   ------------------------
                                     1998           1997
                                   ---------     ----------
<S>                                <C>           <C>
 
Basic income (loss) per share:
 Income (loss) before
  extraordinary item               $     .08     $     (.02)
 
 Extraordinary item                     (.04)             -
                                   ---------     ----------
 
 Net income (loss) per share:      $     .04     $     (.02)
                                   ---------     ----------

Diluted income (loss) per share:
 Income (loss) before
  extraordinary item               $     .07     $     (.02)

 Extraordinary item                     (.04)            -
                                   ---------     ----------

 Net income (loss) per share       $     .03     $     (.02)
                                   =========     ==========
</TABLE> 

                  The accompanying notes are an integral part
                  of these consolidated financial statements.

                                      -6-
<PAGE>
 
                    POLYPHASE CORPORATION AND SUBSIDIARIES
                CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS
                                  (UNAUDITED)

<TABLE> 
<CAPTION> 
                                                     For the Six Months Ended
                                                              March 31,
                                                    ---------------------------
                                                        1998           1997
                                                    ------------   ------------
<S>                                                 <C>            <C>
Cash flow provided by  (used in) operating 
 activities:
 Net income (loss)                                  $   663,465    $  (199,238)
Adjustments to reconcile net income (loss)
 to net cash provided by (used in) operating
 activities:
  Depreciation and amortization                       2,104,938      1,534,924
  Provision for doubtful accounts                       188,701         (8,296)
  Gain on sale of assets                               (987,857)           -
  Accretion of warrants to purchase common stock
     of subsidiary                                          -          219,520
  (Increase) decrease in:
   Accounts and sales contracts receivable              278,349      1,986,390
   Inventories                                       (6,947,947)     1,306,662
   Prepaid expenses and other                           396,166        129,849
   Accounts payable                                   1,631,940     (1,256,817)
   Accrued expenses and other                           148,838     (1,486,209)
                                                    -----------    -----------

      Net cash provided by (used in)
       operating activities                          (2,523,407)     2,226,785
                                                    -----------    -----------

 
Cash flows provided by (used in) investing
 activities:
  Notes and other receivables                        (1,214,554)       437,139
  Receivables from related parties                        7,963     (4,826,425)
  Capital expenditures, net                            (399,328)      (440,996)
                                                    -----------    -----------
 
     Net cash used in
      investing activities                           (1,605,919)    (4,830,282)
                                                    -----------    -----------
</TABLE> 


                  The accompanying notes are an integral part
                  of these consolidated financial statements.

                                      -7-
<PAGE>
 
                     POLYPHASE CORPORATION AND SUBSIDIARIES
          CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (CONTINUED)
                                  (UNAUDITED)

<TABLE> 
<CAPTION> 

                                                     For the Six Months Ended
                                                              March 31,
                                                    ---------------------------
                                                        1998           1997
                                                    ------------   ------------
<S>                                                 <C>            <C>
Cash flows provided by (used in) financing 
 activities:
Borrowings (principal payments) under line of
   credit arrangements, net                         $  2,308,445   $  3,618,528
  Borrowings (principal payments) on other
  notes payable and long term debt, net               25,877,710           -
  Principal payments on term notes                    (1,982,280)          -
  Principal payments on convertible bonds             (4,300,000)          -
  Principal payments on subordinated debentures      (13,000,000)          -
  Redemption of Overhill warrants                     (2,000,000)          -
  Principal collections on Pyrenees note receivable         -           303,774
  Exercise of common stock options                          -            56,600
Dividends on preferred stock                             (80,250)       (75,000)
  Deferred financing costs                            (2,753,552)          -
  Common stock issuance costs                            (17,500)       (17,500)
                                                    ------------   ------------
 
   Net cash provided by
     financing activities                              4,052,573      3,886,402
                                                    ------------   ------------

Net increase (decrease) in cash                          (76,753)     1,282,905
Cash - beginning of period                             1,064,259        280,969
                                                    ------------   ------------

Cash - end of period                                $    987,506   $  1,563,874
                                                    ============   ============
</TABLE> 

                                      -8-
<PAGE>
 
                    POLYPHASE CORPORATION AND SUBSIDIARIES
          CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (CONTINUED)
                                  (UNAUDITED)
<TABLE> 
<CAPTION> 

                                                     For the Six Months Ended
                                                              March 31,
                                                    ---------------------------
                                                        1998           1997
                                                    ------------   ------------
<S>                                                 <C>            <C>
Supplemental schedule of cash flow information:
 Cash paid during the period for :
  Interest                                          $2,594,632     $2,643,554
  Income taxes                                      $      -       $1,311,055
</TABLE> 


Supplemental schedule of noncash investing and financing activities:

In October 1996, an unrelated third party exercised an option to purchase
357,143 shares of common stock.  As consideration, the Company was tendered
125,000 shares of Series A-3 Preferred Stock having a redemption value of
$1,250,000.

In November 1996, a former executive of the Company exercised options on 35,000
of common stock at $.01 per share.  Such options were granted in consideration
for a consulting contract and were valued at $200,000.

In January 1997, an unrelated third party was granted an option on 200,000
shares of common stock, exercisable at $.01 per share, in exchange for a two
year consulting agreement and were valued at $973,000.

In December 1997, in connection with the new Overhill Farms credit agreement,
warrants were issued having a fair market value of $1,200,000.

In connection with the repayment of certain indebtedness to Merrill Lynch, the
Company issued warrants covering 210,000 shares exercisable at $.01 per share
and 210,000 shares exercisable at $1.125 per share.  Such warrants were assigned
a value of $175,000.


                  The accompanying notes are an integral part
                  of these consolidated financial statements.

                                      -9-
<PAGE>
 
                    POLYPHASE CORPORATION AND SUBSIDIARIES
             NOTES TO CONSOLIDATED CONDENSED FINANCIAL STATEMENTS
                                MARCH 31, 1998


1.  NATURE OF BUSINESS

    The Company is a diversified holding company that, through its subsidiaries,
    operates in three industry segments: the food segment, which produces high
    quality entrees, plated meals, soups, sauces and poultry, meat and fish
    specialties; the forestry segment, which distributes, leases and provides
    financing for commercial and industrial timber and logging equipment; and
    the transformer segment, which manufactures and markets electronic
    transformers, inductors and filters.
 
2.  BASIS OF PRESENTATION

    The consolidated financial statements include the accounts of the Company
    and its wholly owned subsidiaries. All material intercompany accounts and
    transactions are eliminated.

    The financial statements included herein have been prepared by the Company,
    without an audit, pursuant to the rules and regulations of the Securities
    and Exchange Commission. Certain information and footnote disclosures
    normally included in financial statements prepared in accordance with
    generally accepted accounting principles have been condensed or omitted
    pursuant to such rules and regulations. The Company believes that the
    disclosures are adequate to make the information presented not misleading.
    The information presented reflects all adjustments (consisting solely of
    normal recurring adjustments) which are, in the opinion of management,
    necessary for a fair statement of results for the interim periods when read
    in conjunction with the financial statements and the notes thereto included
    in the Company's latest financial statements filed as part of Form 10-K.
 
3.  LONG-TERM DEBT

    In December 1997, the Company's subsidiary, Overhill Farms, Inc., refinanced
    a certain portion of existing debt. The new financing amounted to a total
    facility of $24.1 million which is structured as a three-year term loan
    maturing in December 2000. The note requires interest-only payments at prime
    plus 4% (12.5% as of March 31, 1998) through April 1999 and thereafter
    provides for principal amortization of $250,000 per month, plus interest,
    until a final payment of approximately $19,850,000 is due on December 5,
    2000. The agreement also requires Overhill to pay on a quarterly basis,
    service fees totalling $140,000, $300,000 and $440,000 for the first, second
    and third years of the loan, respectively. Under the terms of the new
    financing arrangements, the lender was granted warrants to purchase 30% of
    Overhill's common stock, exercisable immediately, at a nominal value. The
    Company was originally granted the right to repurchase 25% of Overhill's
    shares from the lender over a two year period for consideration of
    $2,000,000. The Company and the lender are currently renegotiating certain
    amendments to the agreement relating to short and long term covenant
    restrictions, as well as the price and percentage for the warrant
    repurchase. Such warrants were assigned a value of $1,200,000, which has
    been recorded as debt discount and is being amortized over the term of the
    loan. Additionally, the lender received fees totalling approximately $1.7
    million in connection with 

                                      -10-
<PAGE>
 
    this financing, which are partially refundable upon early repayment of the
    loan through a refinancing, sale or initial public offering of Overhill. As
    a result of this transaction Overhill repaid in full the $13.0 million
    subordinated debentures and repurchased for approximately $2.0 million the
    warrants previously held by Rice to purchase up to 22.5% of Overhill's
    common stock. These payments to Rice resulted in the Company and Rice
    reaching a settlement of their litigation. The Company also used a portion
    of the proceeds to repay Term Loans A and B due Finova, the $1,500,000
    senior convertible debenture and $2,800,000 of principal of the $4,000,000
    senior convertible debentures due Merrill Lynch. The refinancing also
    enabled the Company and Overhill to cure all previous defaults under various
    loan agreements and provided the Company with approximately $900,000 in
    working capital. The early extinguishment of this indebtedness resulted in
    an extraordinary charge to operations of approximately $616,000 (before
    income taxes) during the quarter ended December 31, 1997. Overhill's credit
    facilities generally restrict loans, advances, dividends or transfers from
    Overhill to the Company to $250,000 per year.

4.  SALE OF SUBSIDIARY

    In December 1997, the Company sold Dallas Parkway Properties, Incorporated,
    a subsidiary whose principal asset was the corporate office building, in
    exchange for nominal consideration plus the assumption of a note payable for
    $2.8 million. The Company realized a gain of approximately $988,000 on this
    transaction.

5.  TAXES

    For the six months ended March 31, 1998, the actual Federal income tax
    expense attributable to income from continuing operations differed from the
    net amounts recorded by the Company. The Company recorded a provision for
    Federal income taxes of $226,000 using the statutory tax rate of 34% and
    then applied a like amount of the existing valuation allowance, resulting in
    a net provision for the quarter of zero. As of March 31, 1998, the Company
    had a remaining valuation allowance of approximately $5.0 million and net
    operating loss carryforwards of approximately $7.3 million.

6.  EARNINGS PER SHARE

    The following table sets forth the computations of basic and diluted
    earnings per share:
<TABLE>
<CAPTION>
 
                                                           For the Three Months Ended
                                                                    March 31,
                                                          -----------------------------
                                                              1998            1997
                                                          ------------    -------------
<S>                                                       <C>             <C>
Numerator:
 Net income (loss)                                         $  (218,106)      (132,001)
 Preferred dividends                                           (39,375)       (37,500)
                                                           -----------    -----------
 Net income (loss) attributable to common shareholders     $  (257,481)   $  (169,501)
                                                           ===========    ===========
 
Denominator:
 Denominator for basic earnings
 per share- weighted average shares (a)                     14,491,396     13,600,432
                                                           ===========    =========== 
</TABLE> 

                                      -11-
<PAGE>
 
<TABLE> 
<CAPTION> 
 
                                                           For the Three Months Ended
                                                                    March 31,
                                                          -----------------------------
                                                              1998            1997
                                                          ------------    -------------
<S>                                                       <C>             <C> 
 Numerator:
  Net income (loss) before extraordinary item              $ 1,279,704    $  (199,238)
  Preferred dividends                                          (80,250)       (75,000)
                                                           -----------    -----------
                                                             1,199,454       (274,238)
  Extraordinary item                                          (616,239)          -
                                                           -----------    ----------- 
  Income (loss) available to common shareholders           $   583,215    $  (274,238)
                                                           ===========    =========== 
 Denominator:
  Denominator for basic earnings per share-
   weighted average shares                                  14,236,542     13,600,432
                                                           -----------    -----------
  Effect of dilutive securities:
   Convertible preferred stock                               1,607,430           -
   Stock options                                               291,478           -
   Warrants                                                    132,618           -
                                                           -----------    -----------
   Dilutive potential common shares                          2,031,526           -  (a)
                                                           -----------    -----------
                                                            16,268,068     13,600,432
                                                           ===========    ===========
</TABLE>

   (a) Dilutive potential common shares were excluded from the computation in
       loss periods since their effect would have been antidilutive.


7. STOCKHOLDERS' EQUITY

   During the period ended March 31, 1998, the holders of the Company's Series F
   6% Preferred Stock converted 7,500 shares into 1,008,355 shares of common
   stock.

   During the quarter ended December 31, 1997, the conversion price of the
   Company's Series A-3 Preferred Stock was adjusted, pursuant to the
   Certificate of Designation for such preferred stock, to market value as of
   the date of conversion.  Accordingly, at March 31, 1998, the Series A-3
   Preferred Stock is convertible into a total of approximately 2.0 million
   shares.

   In connection with the repayment of certain indebtedness to Merrill Lynch as
   described in Note 3, the Company issued warrants covering 210,000 shares
   exercisable at $.01 per share and 210,000 shares exercisable at $1.125 per
   share.  Such warrants were assigned a value of $175,000.


8. LIQUIDITY

   As described in Note 1, the Company operates primarily in three industry
   segments.  The majority of the Company's net sales, operating profit and
   identifiable assets are in the Food and Forestry Groups.  The Company's
   corporate entity has no significant operations and has 

                                      -12-
<PAGE>
 
   historically been partially dependent upon cash flows from its Food and
   Forestry Groups to meet its ongoing liquidity requirements. As a result of
   various restrictions in debt agreements that exist at the Food and Forestry
   Group levels, the Company is generally restricted from receiving management
   fees, dividends, loans or certain other advances in excess of $830,000 per
   year from those subsidiaries.

   In December 1997, in connection with the Long Horizons refinancing, Overhill
   was allowed per the terms of the new note agreement to effect a one-time cash
   advance to Polyphase of $5.5 million.  These proceeds were subsequently used
   by Polyphase to reduce corporate borrowings plus accrued interest by $4.6
   million and provide cash flow for working capital and other needs of
   $900,000.  The remaining proceeds of the $24.1 million Long Horizons note
   were used by Overhill to refinance existing principal plus accrued interest,
   repurchase existing warrants to purchase 22.5% of Overhill's common stock for
   $2 million and pay certain costs related to the financing.  In addition, the
   refinancing enabled the Company and Overhill to cure all previous defaults
   under all of their loan agreements.

   Upon maturity of its note payable to Mr. Harold Estes, former owner of Texas
   Timberjack, Inc. (TTI), the Company, in April 1998, entered into a verbal
   agreement with Mr. Estes to extend the maturity of the note for an additional
   six months on essentially the same terms and conditions as previously in
   effect. The new principal amount of $15,127,000 will bear interest at 16% and
   will become due in October 1998. Mr. Estes has no recourse to any of the
   assets or capital stock of the Company or any of its other subsidiaries other
   than its ownership interest in TTI, except that Mr. Estes holds as secondary
   collateral 2,000,000 shares of the Company's common stock owned by the
   Pyrenees Group, a private investment firm.

   In the event of default on the above note, the Company may be required to
   transfer some or all of its ownership interest in TTI to Mr. Estes and the
   Company would likely incur a noncash loss represented by the difference
   between its net asset position in TTI and the note balance due Mr. Estes.
   Further, as of March 31, 1998, Polyphase is indebted to TTI for approximately
   $6.4 million on a non-interest bearing intercompany advance from TTI offset
   by an intercompany receivable due to Polyphase from TTI of approximately $4.7
   million.  These amounts may be required to be settled in the event of default
   on the Estes note.  Also, in the event of default on this note, if the
   primary collateral, the Company's ownership interest in TTI, is not
   sufficient to satisfy the balance owed to Mr. Estes, it is possible that some
   or all of the Polyphase shares owned and pledged by Pyrenees would be
   retained by Mr. Estes.

   Furthermore, Polyphase may be required to retain legal representation on
   various matters affecting the Company.  The fees to be incurred could be
   substantial in relation to the Company's cash position.

                                      -13-
<PAGE>
 
9. CONTINGENCIES

   On February 23, 1998, Mr. Paul A. Tanner resigned as Chief Executive Officer
   and Chairman of the Company's Board of Directors.  Mr. James Rudis, the
   Company's President was elected by the Board to assume the positions of Chief
   Executive Officer and Chairman.  Following the resignation, a reserve of
   approximately $165,000 was established against outstanding advances due from
   Mr. Tanner.

   The Company has guaranteed the repayment of a loan on behalf of  PLY Stadium
   Partners, Inc. ("Stadium Partners"), a private investment firm headed by the
   former Chairman of the Company, Mr. Paul A. Tanner.  The loan was made by a
   financial institution in connection with the purchase of land by a
   partnership affiliated with Stadium Partners to build a multi purpose stadium
   in Las Vegas.  The guarantee is effective, in certain circumstances or upon
   the occurrence of certain events, including without limitation if the Nevada
   Partnership files for bankruptcy or insolvency, if representations by the
   partnership prove to be fraudulent regarding the financial condition of the
   partnership, the land securing the loan is further encumbered or ownership is
   transferred without the consent of the lender.  The aforementioned
   partnership is currently in default on its loan from Lehman, and foreclosure
   proceedings by Lehman were initiated in January of this year.  A foreclosure
   sale was scheduled for May 4, 1998.  Stadium Partners filed for protection
   pursuant to Chapter 11 of Title 11 USC (S) 101 et. seq. on May 1, 1998.  The
   foreclosure sale has been temporarily postponed pending judicial
   intervention.  Notwithstanding such actions the Company, based on the advice
   of legal counsel, considering available defenses and the fair market value of
   the real estate, does not believe that it will incur any significant
   liability as a result of this guarantee.  As a result, the Company believes
   the existence of such guarantee will not have a material adverse effect on
   the Company's financial condition or results of operations.

   During 1997, five substantially identical complaints were filed in the United
   States District Court for the District of Nevada against the Company and
   certain of its officers and directors. The suits seek class action status and
   assert liability based on alleged misrepresentations that resulted in the
   market price of the stock being artificially inflated.  The Company intends
   to vigorously defend these actions.  One of these lawsuits was subsequently
   dismissed.

                                      -14-
<PAGE>
 
ITEM 2. MANAGEMENT'S DISCUSSION  AND ANALYSIS


Statements contained in this Form 10-Q that are not historical facts, including,
but not limited to, any projections contained herein, are forward-looking
statements and involve a number of risks and uncertainties.  The actual results
of the future events described in such forward-looking statements in this Form
10-Q could differ materially from those stated in such forward-looking
statements. Among the factors that could cause actual results to differ
materially are: adverse economic conditions, industry competition and other
competitive factors, government regulation and possible future litigation.


RESULTS OF OPERATIONS

Revenues for the six months ended March 31, 1998 decreased $3,854,000 (5%) to
$70,721,000 from $74,575,000 during the six months ended March 31, 1997.  The
decrease in revenue is primarily attributable to the elimination of low margined
business at Overhill Farms.  On a consolidated basis, gross margins increased
over the comparable period in the prior year from 16% to 19%, resulting in
increased operating income despite slightly higher selling, general and
administrative expenses.  For the six months ended March 31 1998, operating
income increased $821,000 (24%) to $4,281,000 from $3,464,000 during the
comparable period in 1997.

Interest expense increased $699,000 over the comparable period primarily due to
the refinancing of the Company's indebtedness to Harold Estes.

Net income before extraordinary item for the six months ended March 31, 1998
increased $1,479,000  to  net income of $1,280,000 from a net loss of  $199,000
during the six months ended March 31, 1997.  Net income for the period included
a one time gain of $988,000 from the sale of the Company's corporate
headquarters in December 1997.  Net income was adversely affected by an
extraordinary expense of $616,000, the early extinguishment of debt, associated
with the refinancing of certain indebtedness by Overhill Farms.

The Food Group's revenues decreased to $45,345,000 for the six months ended
March 31, 1998 as compared to $48,732,000 for the six months ended March 31,
1997.  Operating income remained flat  at $2,571,000, compared to $2,561,000 in
the prior year.  Revenues have decreased primarily due to the paring of  lower
margined business and the improvement in the quality of sales, increasing
Overhill's gross margins by 1.5%  for the period.

Revenues for the Timber Group for the six months ended March 31, 1998 decreased
$798,000 (3%) to $23,282,000 from $24,080,000 for the six months ended March 31,
1997. Operating income for the comparable period increased $1,094,000 (77%) to
$2,506,000 for the six months ended March 31, 1998 from $1,412,000 for the six
months ended March 31, 1997.    Sales of new equipment decreased  during the
period as sales of used equipment remained strong generating a product mix with
higher gross margins than the comparable period in 1997.  For the six months
ending March 31, 1997 gross margins rose  7.0% to 24.3 % from 17.3% in 1997.

Revenues in the Transformer Group for the six months ended March 31, 1998
increased $330,000 to $2,093,000 from $1,763,000 for the comparable period in
fiscal 1997.  Operating income 

                                      -15-
<PAGE>
 
decreased to $29,000 for the six months ended March 31, 1998 from $43,000 for
the comparable period in fiscal 1997. This decrease is primarily attributable to
the competitive market and the lower profit margins on government contracts.


LIQUIDITY AND CAPITAL RESOURCES

During the six months ended March 31, 1998, the Company used cash of
approximately $2,523,000 in its operating activities compared to cash provided
of $2,227,000 during the comparable period in fiscal 1997. The increased use of
cash over the comparable period resulted primarily from increases in inventories
at Overhill and Timberjack.

During the six months ended March 31, 1998, the Company's investing activities
used cash of approximately $1,606,000 compared to a use of cash in the amount of
$4,830,00 in fiscal 1997.  The Company's use of cash consisted primarily of new
notes receivable.

During the six months ended March 31, 1998, the Company's financing activities
provided cash of approximately $4,053,000 as compared to cash provided of
$3,886,000 in the comparable period in fiscal 1997.  The source of cash during
the period consisted primarily from the loan facility of approximately $24
million at Overhill Farms.

The Company plans to continue its program of expansion and diversification
through the acquisition of additional operating companies.  Funding for these
acquisitions is anticipated to come primarily from a combination of internally
generated funds and from additional borrowings.  The Company's management
believes that cash generated from operations, together with available lines of
credit and contemplated debt and/or equity placements, will be sufficient to
meet the Company's liquidity requirements for the next 12 months.


ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK

The Company does not own, nor does it have an interest in any market risk
sensitive investments.

                                      -16-
<PAGE>
 
                          PART II - OTHER INFORMATION


ITEM 1.  LEGAL PROCEEDINGS

During 1997, five substantially identical complaints were filed in the United
States District Court for the District of Nevada against the Company and certain
of its officers and directors. The suits seek class action status and assert
liability based on alleged misrepresentations that resulted in the market price
of the stock being artificially inflated.  The Company intends to vigorously
defend these actions.  During the six month period ended March 31, 1998, one of
these lawsuits was dismissed.


ITEM 6.  EXHIBITS AND REPORTS ON FORM 8-K.

         (a)  Exhibits
 
         27   Financial Data Schedule


         (b)  Reports on Form 8-K - The following reports were filed on Form 8-K
              during the quarter ended March 31, 1998.

         None

                                      -17-
<PAGE>
 
                                  SIGNATURES


In accordance with the requirements of the Securities Exchange Act of 1934, the
registrant caused this report to be signed on its behalf by the undersigned,
thereunto duly authorized.


                                         POLYPHASE CORPORATION
                                         (REGISTRANT)


Date: May 18, 1998                       By: /s/ James Rudis
                                             --------------------------------
                                             James Rudis
                                             Chairman, President and
                                             Chief Executive Officer



Date: May 18, 1998                       By: /s/ William E. Shatley
                                             --------------------------------
                                             William E. Shatley
                                             Senior Vice President, Treasurer
                                             and Chief Financial Officer

                                      -18-
<PAGE>
 
                               INDEX TO EXHIBITS


 Exhibit No.                                          Exhibit
-------------                                 -----------------------

  27                                          Financial Data Schedule