INSTRUCTION MANUALPADDLE TYPE LEVEL SW ITCH

MODEL： PRL-300

Meanings of indications for safety used in this Instruction Manual are as follows.
WARNING:

Indicates that improper handling assumes the risk of a fatal or serious injury.

CAUTION:

Indicates that improper handling assumes the risk of injury or damage to property only.

TOWA SEIDEN INDUSTRIAL CO., LTD.
HEAD OFFICETOKYO OFFICENAGOYA OFFICE

Phone: 81-6-6340-5522, Fax: 81-6-6340-5519
Phone: 81-3-5484-2171, Fax: 81-3-5484-2175
Phone: 81-52-937-5817, Fax: 81-52-937-5836OSAKA PLANT

Phone: 81-6-6340-2831, Fax: 81-6-6349-6551

URL http://w w w .tow a-seiden.co.jp№EPR30002015.04.13

Paddle Type Level Switch (Model: PRL-300) Instruction ManualContents
1. Operating principles ...................................................... 2
2. Precautions for use
a. Determination of the mounting location ................................. 2
b. Impact of power and particles and vibration of the hopper .............. 2
c. Relationship with transportation facilities ............................ 2
3. Precautions for connection
a. Color coding of external terminals
a-1. Signals ............................................................ 3a-2. Checking method of signal switching ................................ 3b. Electric wires to be usedb-1. Connection of electric wires to be used ............................ 3b-2. Cables to be used .................................................. 3b-3. Electric wire mounting fittings .................................... 3
c. Detachment and attachment of a cover .................................... 4
4. Inspection .................................................................. 4
5. Torque adjustment ........................................................... 4
6. Repair methodMounting of paddles ........................................................ 57. Method of assembly inspection
a. Confirmation of wiring connection ....................................... 5b. Confirmation of insulation resistance ................................... 5c. Inspection method ....................................................... 5
8. Internal wiring and lead wire ............................................... 5
9. Internal equipment .......................................................... 6
10. Problem examples (typical examples) ........................................ 6
Reference structural drawing ................................................... 711. Operating Principles

The motor (c) is placed at a position (e) because of the spring (g) and the shaft(b) rotates with the mounted paddle (a). If rotation of the shaft (b) is restrictedby sediment together with the paddle (a), the motor (c) overcomes the spring (g)by the internal reduction gear (j) to rotate around the shaft of motor (d) andtilt toward the (h) side, and the level detection signal is output by the micro
switch (f). Then, the motor (c) is stopped by the micro switch (i).
2. Precautions for use

a. Determination of the mounting location
Mount a level switch on a location where the level of powder and particles
actually changes.

b. Impact of powder and particles
When the level switch is mounted just under the point where powder andparticles fall, it may be broken by impact such as an arching phenomenon in
the hopper. Change the mounting location or mount a protection plate.
Vibration of the hopper
Do not mount the switch at a location where mechanical vibration of the hopper
itself and vibration of the vibrator and others continuously apply for a longtime whenever possible.
c. Relationship with transportation facilitiesFor example,
Full: mount the switch at a location where if all remaining materials on theconveyor are put in, no material overflows.
Empty: mount the switch at a location where the time when the hopper empty
signal is output, the conveyor rotates and raw materials are fed isanticipated.

2

3. Precautions for connection
a. Color coding of level switch external terminals is as follows:

a-1. Signals
L green (blue): conduction to “C” in the condition where no measured object comes
into contact with the paddle (During rotation of the paddle)
C yellow: the neutral point of signals (common of a contact point)
H red: No conduction to “C” in the condition where no measured object comes into
contact with the paddle
a-2. Checking method of signal switching
Slightly twist the paddle approximately 20 degrees counterclockwise.
Conducted between C and H
No longer conducted between C and L
When the paddle is twisted strongly, a slight and metallic clicking noise isgenerated and the paddle idles by 90 degrees. This is caused by operation of theslip mechanism and there is no problem.

b. Electric wires to be usedb-1 Crimp an electric wire to be used on a crimp-type terminal via a strand wire
to connect to an internal terminal.
*Do not use single wires whenever possible.
b-2 When using cables, use cables with a finished outside diameter of φ10 to 11.
Example:CVV (vinyl cable for control)
1.25mm2, 4 cores, finished outside diameter φ112mm2, 3 cores, finished outside diameter φ11VCT (vinyl cap tire cable)
0.75mm2, 5 cores, finished outside diameter φ10.5
1.25mm2, 4 cores, finished outside diameter φ10.5
b-3 Securely tighten electric wire mounting fittings after wiring. As rubber packing
is in a fitting, tighten the cable to prevent rain and moisture. If the cableis loose tightened, rain and dust will enter the fitting and cause the switch
to malfunction. Also, the same applies if a fitting that does not match withthe size of a cable is used.

3c. Detachment and attachment of a cover
Screws of ISO 5mm are used for a cover.

If screws are not securely tightened, rain, moisture and dust will enter theswitch as with b-4, causing a malfunction.

4. Inspection
Remove the front seal cap before inspection of a seal.
The seal cap is a right-handed type.
Keep in mind that the shaft and paddle boss are left-handed types. As for inspectionof the internal equipment, if the rear case is removed in the same way as thetime of connection, the operating condition of the limit switch can be confirmed.
And the mechanism can be removed by loosening the two (+) screws tightened on
the right and left sides of the frond case. Pay special attention to lead wires
at this time.
5. Torque adjustment
The torque adjustment of the shaft is provided on the mechanism mounting plate.
Torque can be adjusted by changing the latching position of the spring.

Mechanism mounting plate back side4

6. Repair method
Mounting of paddles on the shaft is as follows:
The screw (A) is a left-handed type. The nut (5)is screwed on the shaft (12) to put the spring
washer in and the paddle boss (3) is screwed on.
Keep in mind that a screw lock agent is used forthe screw portion.

7. Method of assembly inspection
a. Make sure that wiring is correctly connected using a tester.
b. Make sure that there is the insulation resistance between each terminal andthe earth using a Megger.
c. c-1 Turn on power.
c-2 Make sure that the paddles and the shaft rotate smoothly.
c-3 Make sure that signals change by touching the paddles by hand or puttinga hand into the powder.
(2 or 3 locations during one rotation)
c-4 Make sure that rotation of the shaft slips by restricting rotation of
the paddle by hand.
(2 or 3 locations during one rotation)5

9. Internal equipment

10. Problem examples (typical examples)a. Problem caused by a short circuit accident of the micro switch

When the micro switch is wired into the internal equipment, it is wired to thealarm side (L, C, H) instead of the power side.
◎Make sure to energize the switch after confirmation of the side to be wired.

b. Poor tightening of the cover◎

Make sure to securely tighten the cover.

c. Problem caused by damage to the screws on the terminal block/cover◎

Make sure to tighten screws using the appropriate driver.

Be careful not to touch the terminal block with fingertips, etc. (Watch outfor electric shock)6

Reference structural drawing

8MetalBsBM

167

GreaseU-ret EI-1

15

6

Seal cap

BsBM (plating)145

Oil seal

Nitrile rubber 10-20-7

4Seal

3

Motorcoupling
boss
Torque adjustment
plate

SS400
quenchingcarbonSPC (plating)

23

Insulation sheet

Ball

High-carbon
bearing steel

22

Terminal

13

Plate spring

Spring steel

21

Teflon t0.5

12Snap ring for hole

Spring steel

20

Shaft couplingboss
Micro switch

Shaft

SUS30411

Bearing

6000ZZ

19

Actuating bar

SS400
chromate
plating

2Washer

M8 Left SUS

10Spring steel

18

CoverAluminum casting

1PaddleSUS304

9

Aluminum casting

17

Motor

PTM-12EG MS

No

Parts name

Description

No

Description

No

Snap
shaft
Case

ringforParts name7

Parts name

5P
SS400
chromate
plating

Description