Abstract:
A vacuum cleaner is reconfigurable between at least two positions. The vacuum cleaner has at least one motor and fan assembly for receiving power and producing airflow during use of the vacuum cleaner. The vacuum cleaner also has at least one sensor adapted to sense a change in the position of the vacuum cleaner and to alter the power provided to the at least one motor and fan assembly in response thereto.

Description:
Divisional application of U.S. patent application Ser. No. 09/576,249 filed on May 24, 2000, now U.S. Pat. No. 6,457,205, Oct. 1, 2002. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a vacuum cleaner having a plurality of power modes and more specifically to a power control system for such a cleaner. 
     BACKGROUND OF THE INVENTION 
     Historically, power control systems for vacuum cleaners have been designed to provide a uniform flow of power. In the case of vacuum cleaners with electrical motors, power delivery systems have been designed so as to ensure a continuous flow of electricity to the motor so that the drive shaft driven by the motor runs at a constant rate of revolution. 
     More recently, developments have been directed towards providing variable speed control for vacuum motors. U.S. Pat. No. 6,008,608, which issued to Holstein et al., discloses a switch and speed control assembly for an electronically controlled vacuum cleaner motor. Holstein et al. &#39;608 provides a control member coupled to a voltage varying device that regulates the amount of power supplied to the vacuum cleaner motor control circuit. The control member includes a thumb wheel which is operated by the user to manually adjust the voltage varying device to selectively vary the speed of the vacuum cleaner motor. Holstein et al. &#39;608 teaches that a spring may apply a counterforce to the control member to return the motor speed to a normal operating condition after momentarily engaging a “high on” mode. Thus, in Holstein et al. &#39;608, the user must manually operate the control member. 
     In U.S. Pat. No. 4,969,229, which issued to Svanberg et al., a battery operated surface treatment apparatus having a booster function is disclosed in which a separate battery is connected in series with the batteries in the main power supply unit in order to temporarily boost the power. A knob is manually operated to activate the booster function. A timing control is optionally provided to limit the period of operation of the booster function in order to prevent overheating. Svanberg et al. &#39;229 indicates at column 1, lines 27-31, that the invention is directed to vacuum cleaners not provided with any electronic speed control. 
     In U.S. Pat. No. 4,811,450, which issued to Steadings, a vacuum cleaner having an auxiliary cleaning means is disclosed. The auxiliary cleaning means of Steadings &#39;450 includes a flanged portion which is used to divert the suction force in a main suction air channel into an auxiliary cleaning hose. According to Steadings &#39;450, during auxiliary cleaning, an increased suction force may be created in the auxiliary hose by closing off the air flow in the main suction air channel, thereby relieving part of the load on the common suction motor. Steadings &#39;450 explains that such relief results in increased rotational speed of the motor, which in turn correspondingly increases the suction air flow in the auxiliary hose. However, Steadings &#39;450 makes it clear, at column 1, lines 54-60, that in the auxiliary mode, the increase in the operational speed of the suction motor is obtained without requiring any electronic motor control or regulation. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a vacuum cleaner having a plurality of power modes, and to a power control system which is capable of maintaining the cleaning performance of the vacuum cleaner in those various power modes and/or of controlling the power output to extend the operational life of a battery operated vacuum cleaner. Briefly, the power control system includes one or more sensors or switches which are used to sense the mode of operation of the vacuum cleaner. Signals from the one or more sensors or switches are then directed to a microprocessor which in turn varies a power supply signal being provided to the vacuum cleaner motor. 
     In accordance with an aspect of the present invention, there is provided a vacuum cleaner having a plurality of operating modes, comprising: 
     (i) at least one motor and fan assembly for receiving a power supply signal and producing a suction airflow during use of the vacuum cleaner; 
     (ii) at least one sensor for automatically sensing a change in the operating mode of said vacuum cleaner and generating a mode signal in response thereto; and 
     (iii) a microprocessor responsive to said mode signal and adapted to vary said power supply signal. 
     In a preferred embodiment, the vacuum cleaner has a plurality of distinct operating positions and at least one sensor is adapted to sense a change in the operating mode based on a change in the operating position of said vacuum cleaner. 
     In another embodiment, the vacuum cleaner comprises a cleaning head and a main casing pivotally connected to said cleaning head, and at least one sensor is adapted to sense when said main casing is positioned generally vertically above said cleaning head to sense that said vacuum cleaner is in standby operating mode. 
     In yet another embodiment, the vacuum cleaner comprises a cleaning head, a main casing pivotally connected to said cleaning head and an auxiliary hose, and at least one sensor is adapted to sense when said main casing is positioned generally vertically above said cleaning head and said vacuum cleaner is configured such that said auxiliary hose is in airflow communication with said motor and fan assembly and to generate a high flow mode signal in response thereto. 
     In another embodiment, the vacuum cleaner is an upright vacuum cleaner and further includes an auxiliary hose connectable in airflow communication with said motor and fan member assembly, and a high flow mode sensor for sensing when said auxiliary hose is in use. 
     More preferably, the vacuum cleaner includes a receptacle for releasably receiving said auxiliary cleaning hose, said high flow mode sensor being provided in said receptacle for sensing when said auxiliary cleaning hose is released from said receptacle. 
     In an alternative embodiment, the vacuum cleaner further comprises at least one power supply for generating said power supply signal. The power supply may comprise a rechargeable battery. 
     In an embodiment including a rechargeable battery, the vacuum cleaner preferably includes at least one sensor adapted to sense when said vacuum cleaner is in battery recharge mode and to generate a recharge mode signal in response thereto, said microprocessor being responsive to said recharge mode signal and being adapted to vary said power supply signal to operate said motor in a low flow mode, whereby airflow is produced to cool said battery during recharge. 
     In another aspect of the present invention, there is provided a vacuum cleaner having a plurality of operating modes, comprising: 
     (i) suction means for receiving a power supply signal and producing a suction airflow during use of the vacuum cleaner; 
     (ii) sensor means for sensing a change in the operating mode of said vacuum cleaner and generating a mode signal in response thereto; and 
     (iii) processor means responsive to said mode signal and adapted to vary said power supply signal. 
     In a preferred embodiment, the vacuum cleaner has a plurality of distinct operating positions and the sensor means is adapted to sense a change in the operating mode based on a change in the operating position of said vacuum cleaner. 
     In another embodiment, the sensor means includes a standby mode sensor for sensing a standby mode and generating a standby mode signal in response thereto, said processor means being adapted to vary said power supply signal in response to said standby mode signal so that said suction means is operated at decreased power as compared to normal mode when said vacuum cleaner is used to clean a surface. 
     In yet another embodiment, the sensor means further includes a high flow mode sensor for sensing a high flow mode and generating a high flow mode signal in response thereto, said processor means being adapted to vary said power supply signal so that said suction means is operated at increased power as compared to the normal mode. 
     In an embodiment including a rechargeable battery, the vacuum cleaner preferably includes a battery recharge mode sensor for sensing a battery recharge mode and generating a battery recharge mode signal in response thereto, said processor means being adapted to vary said power supply signal to operate said suction means in a low flow mode, so that airflow is produced to cool said battery during recharge. 
     In yet another aspect of the present invention, there is provided a vacuum cleaner having a plurality of operating modes, comprising: 
     (i) at least one motor and fan assembly for receiving a power supply signal and producing a suction airflow during; use of the vacuum cleaner, said vacuum cleaner having a plurality of distinct operating positions, each of said operating modes corresponding to one of said distinct positions; 
     (ii) at least one switch for generating a mode signal corresponding to at least one of the operating modes; and 
     (iii) a microprocessor responsive to said mode signal and adapted to vary said power supply signal. 
     In one embodiment, the vacuum cleaner includes a standby mode switch for generating a standby mode signal when said vacuum cleaner is in a standby mode position, said processor means being adapted to vary said power supply signal in response to said standby mode signal so that said motor and fan assembly is operated at decreased power as compared to normal mode when said vacuum cleaner is used to clean a surface. 
     In another embodiment, the vacuum cleaner includes a high flow mode switch for generating a high flow mode signal when said vacuum cleaner is in a high flow mode position, said processor means being adapted to vary said power supply signal in response to said high flow mode signal so that said motor and fan assembly is operated at increased power as compared to normal mode when said vacuum cleaner is used to clean a surface. 
     In yet another embodiment, the vacuum cleaner includes a battery recharge mode switch for generating a battery recharge mode signal when said vacuum cleaner is in a battery recharge mode position, said processor means being adapted to vary said power supply signal to operate said motor and fan assembly in a low flow mode, so that airflow is produced to cool said battery during recharge. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other advantages of the instant invention will be more fully and particularly understood in connection with the following description of the preferred embodiments of the invention in which: 
     FIG. 1 is a schematic of a circuit which may be used in a power control system for a vacuum cleaner according to an embodiment of the present invention; 
     FIG. 2 is a cross-section of a vacuum cleaner including the circuit of FIG. 1, shown operating in normal mode; 
     FIG. 3 is a cross-section of the vacuum cleaner of FIG. 2 shown operating in standby mode; 
     FIG. 4 is a cross-section of the vacuum cleaner of FIG. 2 operating in high flow mode with an auxiliary cleaning hose detached from the main casing; and 
     FIG. 5 is a partial break away top plan view of the vacuum cleaning head of FIG. 2 including a battery and a separate cooling motor and fan assembly. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The teachings of the present invention are directed to improving the performance and efficiency of vacuum cleaners in general, and more specifically to maintaining the efficiency of the vacuum cleaner in various operating modes by means of a power control system. 
     By operating the vacuum cleaner in one of a plurality of possible operating modes, depending on the cleaning task, a degree of improved performance and efficiency will be achieved. As mentioned, possible operating modes may include a “normal” operating mode, a “high flow” mode for auxiliary cleaning, a “standby” mode for reduced speed during interruptions in vacuuming, and a “battery recharge” mode for battery operated vacuum cleaners. 
     Referring to FIG. 1, a motor control circuit is shown which may be used in a vacuum cleaner in accordance with the instant invention. FIGS. 2,  3  and  4  exemplify a vacuum cleaner which may include the circuit of FIG.  1 . It will be appreciated that the vacuum cleaner may be of any construction known in the art. As shown in FIG. 2, a vacuum cleaner  70  has vacuum cleaner head  72  and main casing  74 . FIG. 2 shows the vacuum cleaner  70  operating in the normal floor cleaning mode referred to earlier (i.e. cleaning head  72  is being used to clean the surface over which cleaner head  72  travels). Cleaning head  72  has rear wheels  76  and front wheels  78  to enable movement of cleaning head  72  across a surface. Cleaning head  72  is provided with a rotatably mounted brush  80  which is positioned above air inlet  82 . Cleaning head  72  has an air outlet  84  positioned at the end of air flow path  86 . 
     Main casing  74  contains the filtration means which preferably comprises cyclone housing  90  defining cyclone chamber  92 . Cyclone chamber  92  is provided with an air inlet  94  which is in air flow communication with air outlet  84  by means of air flow path  100 . 
     Motor  98  is positioned above and downstream from air outlet  96 . Outlet  108  from vacuum cleaner  70  is provided downstream from motor  98 . Additional filtration means may be provided, if desired, in one or both of chambers  104  and  106 . Handle  110  is provided so as to enable the vacuum cleaner to be pushed by a user. 
     Now referring to FIG. 3, the vacuum cleaner  70  of FIG. 2 is shown in the standby mode referred to earlier. Rotatable valve  88  is provided in the cleaning head  72  so as to isolate the filtration means in main casing  74  from air flow path  86  when the vacuum cleaner  70  is in the upright position (i.e. the main casing  74  is positioned generally vertically over the cleaning head  72 ). 
     A first microswitch  140  senses when the vacuum cleaner  70  is in the upright position and sends a signal to a microcontroller  116  (FIG. 1) to vary the power signal to cause the motor to operate on standby, as will be explained further below. It will be appreciated that air flow paths  86  and  100  need not be isolated to utilize the standby mode. 
     Now referring to FIG. 4, as shown, vacuum cleaner  70  may also be adapted for above floor cleaning by means of an auxiliary cleaning hose  102  which is releasably connectable to main casing  74  by any means known in the art. A second microswitch  146  detects that the hose  102  has been removed from its receptacle and sends a signal to the microcontroller  116  to cause the motor to operate in the high flow mode referred to earlier, and as described further below. In the embodiment of the vacuum cleaner  70  shown in FIG. 4, it is preferable that the vacuum cleaner  70  first be put into the standby mode as shown in FIG. 3 so that all of the air travels through hose  102 . Consequently, a vacuum cleaner  70  may go through an intermediate standby mode when switching between the normal mode and the high flow mode described above. However, it will be appreciated that this need not be the case in another vacuum cleaner configuration. In fact, it will be appreciated by those skilled in the art that the motor control circuit of the instant application may be utilized with virtually any vacuum cleaner, such as with a vacuum cleaner using any filtration means known in the art, as well as any type of vacuum cleaner, e.g. upright, canister, back-pack and central vacuum systems. 
     According to one aspect of the instant invention, the motor control circuit may be utilized with a vacuum cleaner which is to be plugged into a standard electrical outlet in a house. In such a case, the power control system may be designed to provide full power in the high flow mode and to reduce the current provided to the motor in the normal mode. Alternately, the power control system may also be used with a vacuum cleaner which is powered by batteries and preferably rechargeable batteries. In such a case, the power control system may be designed to provide a standard level of power in the normal mode and to increase the power drawn from the batteries during the high flow mode. Preferably, in such a case, the power control system also controls the charging and discharging the batteries. 
     Referring back to FIG. 1, power control circuit  112  comprises a motor controller as well as a battery charger. Battery  114  supplies 50% of the power for motor  98  as DC current. The other half of the power is supplied to the motor through an inverter (namely field effect transistor  120  and transformer  122 ). This has the advantage that half the power is transmitted as DC (which has nominal circuit losses) and half is transmitted through the inverter (which may have an efficiency of eg. about 85%) for an overall efficiency of about 92.5%. It is recognized that by increasing the power channelled through the inverter, the flow rate of the mechanical system can be controlled. However, increasing the power channelled through the inverter increases the heat losses through the circuit and mitigates a portion of the energy saving realized in the fluid mechanical portion of the system. It will be appreciated the battery  114  may supply all of the power to motor  98  through the inverter circuit resulting in about a 7.5% reduction in the power savings. The instant design also advantageously allows multiple power levels to be supplied to motor  98 . 
     Still referring to FIG. 1, the vacuum cleaner is operated by a user turning the vacuum cleaner on by an on/off switch  118 , which may be any switch known in the art. When vacuum cleaner  70  is turned on, microcontroller  116  receives a signal from switch  118  and in turn starts to oscillate field effect transistor  120  at a high frequency (e.g. about 60 KHz). Circuit  112  is provided with transformer  122  having primary and secondary coils  124  and  126 . The high frequency oscillation produced by field effect transistor  120  causes primary coils  124  to induce a high voltage in secondary coils  126 . The high voltage induced in second coil  126  is switched on and off by field effect transistor  128  at a much lower frequency (e.g. 9 Hz) as controlled by microcontroller  116  by means of wire  152  to create a pulse train signal. The high voltage induced in second coil  126  may also be supplied to diode multiplier  172  to provide current to, eg. an electrostatic generator in vacuum cleaner  70 . 
     Field effect transistor  128  is connected to motor  98  via wire  130 , switch  132  and wire  134 . Accordingly, the pulse train developed by field effect transistor  128  is supplied to motor  98  so as to cause sub-rotational accelerations as described herein whereby the efficiency of the power transfer from motor  98  to the fluid stream passing through vacuum cleaner  70  is improved. 
     In a cyclonic vacuum cleaner, the impulses are preferably 1/81 seconds long having a voltage (amplitude) six times greater than the DC voltage supplied by battery  114  to motor  98  by means of wires  136 ,  138 . The frequency of the pulses produced by field effect transition  128  is preferably 6-20 Hz for a cyclonic vacuum cleaner using a series universal motor wound to produce the desired flow rate when 50 volts AC is applied with  200  watts available. It will be appreciated that the pulse which is provided to motor  98  may be varied by changing the frequency of field effect transistor  128 . 
     Still referring to FIG. 1, in accordance with another aspect of this invention, circuit  112  may include a first microswitch  140  which is activated when vacuum cleaner  70  is placed in the upright standby position shown in FIG.  3 . Microswitch  140  may be of any known in the art which will provide a signal to microcontroller  116  when upper casing  74  is in the upright position shown in FIG.  3 . In the embodiment shown in FIG. 3, the upright position is sensed due to engagement between upper casing  74  and microswitch  140 . Alternatively, the sensor may be mounted on upper casing  74  to engage the vacuum cleaner head  72  and sense when upper casing  74  is in the upright position or the sensor may sense when upper casing  74  extends generally vertically. It will be understood that the sensor may be provided at any other location where it can sense the upright position (e.g. the sensor may be provided at the pivot point between the vacuum cleaner head  72  and the upper casing  74 ). 
     As explained earlier, first microswitch  140  causes a signal to be sent to microcontroller  116  by means of wire  142 . This causes microcontroller  116  to terminate the oscillation of field effect transistors  120  and  128  thereby reducing the power consumption and air flow through motor and fan blade assembly  98 . 
     Typically, a user may leave a vacuum cleaner running when in the upright position when attending to other tasks associated with vacuuming such as to move furniture or other objects which may be in the way. When first microswitch  140  is actuated, moving the vacuum cleaner into a standby mode, the power consumed by motor and fan blade assembly  98  is reduced thereby permitting a user to move furniture, answer the telephone or the like while reducing the power consumption of motor and fan blade assembly  98 . Microswitch  140  may be utilized to switch a vacuum cleaner operating from a standard electrical outlet to a standby mode. This may be advantageous to decrease the noise produced by vacuum cleaner  70  when it is not being used. However, use of the standby mode is particularly advantageous in a battery powered vacuum cleaner in order to conserve the battery. 
     Now referring to FIG. 4, optionally, hose  102  is detachable from main casing  74 , e.g., in the direction of arrow B so as to enable above the floor cleaning. Hose  102  may have a crevice cleaning tool or other attachment  144  slidably received therein in the direction of arrow C. In such a case, circuit  112  preferably also includes a second microswitch  146  for switching motor and fan blade assembly  98  to a high flow mode. The higher flow is desirable for enhanced cleaning using the accessory tools  144 . Alternately, as the use of a length of hose causes additional pressure losses, increasing the power provided to motor and fan blade assembly  98  may result in the same flow rate through the filtration means when hose  102  is used. Microswitch  146  may be provided in the receptacle in which hose  102  is received and actuated when hose  102  is released from the receptacle (in the direction of arrow B). Microswitch  146  may be a pressure actuated switch (i.e. the switch may have a button which is pressed inwardly) or may be a proximity switch which senses the presence of hose  102  in its receptacle. When hose  102  is released, the button extends outwardly thereby sending a signal to microcontroller  116  by means of wire  148 . In response to this signal, microcontroller  116  sends a signal to field effect transistors  120  and  128  by means of wires  150  and  152  respectively. This causes field effect transistor  120  to oscillate at a high frequency (e.g. 60 KHz or greater) and cause field effect transistor  128  to oscillate at a higher frequency than before (e.g. 11-15 Hz) with pulses of, e.g. 1/81 to 1/60 of a second for a typical cyclonic vacuum cleaner as described above. The longer pulse width and/or greater frequency of pulses delivered to motor and fan blade assembly  98  produces a higher flow of air through vacuum cleaner  70  then when the vacuum cleaner is drawing dirt laden air through inlet  82 . 
     Microcontroller  116  also preferably includes a circuit for determining a level of charge remaining in battery  114 . To this end, microcontroller  116  sends a signal to field effect transistor  120  which causes field effect transistor to switch on for a short period (e.g. approximately 0.1-0.2 seconds). This produces an impulse equivalent to DC. As the frequency of this impulse is very low, transformer  122  effectively becomes a low resistance short circuit across battery  114  thereby causing a current surge through low value resistor  154  which is series with transformer  122 . 
     The voltage drop across low value resistor  154  caused by the current surge is conducted to (e.g.) the analog to digital port of microcontroller  116  by means of wires  156  and  158 . While the voltage which is supplied by battery  114  may be relatively constant over a substantial portion of the operating life of a battery (e.g. 75% or more), it has surprisingly been determined that the rate of rise of current in response to a momentary short circuit does not remain constant. In particular, as the capacity of the battery is reduced (i.e. charge is withdrawn from the battery), the ability of battery  114  to supply a current surge is also reduced. Therefore, it is possible to determine the capacity remaining in the battery by occasionally producing a short circuit across battery  114  and monitoring the rate of rise of the current in response to the short circuit. For a NiMH sub C battery pack comprising two sets of twelve sintered cells connected in parallel, the di/dt varies from 300 A/S to 120 A/S from 90% capacity to 20% capacity while the voltage output is essentially constant. Thus, by knowing the di/dt relationship for a battery over the capacity for a battery, microcontroller  116  may provide a signal indicating the amount of capacity remaining in the battery or, if the battery is being charged, the degree to which the battery has been charged. 
     The same method may be utilized during the recharging of the battery to determine the charge state of the battery. Typically, the charge state of the battery is determined using the −ΔV. When a battery is in the −ΔV range, it is already overcharged. Rechargeable batteries are subject to degradation if their temperature increases too much, which occurs when they are overcharged. Therefore, it is advantageous to determine the charged state of a battery prior to the battery becoming overcharged. Accordingly, during the recharging of a battery, microcontroller  116  may cause field effect transformer  120  to occasionally emit a low frequency pulse thereby producing a current surge which may be measured by the voltage drop across low value resistor  154 . 
     Preferably, microcontroller  116  includes means for opening the circuit to thereby shut off motor and fan blade assembly  98  when battery  114  is at a sufficiently low charge level. Accordingly, circuit  112  may shut down the power drawn from battery  114  by opening relay  160  which opens the circuit to motor and fan blade assembly  98  and by terminating the signals which are send to field effect transistors  120  and  128 . 
     It will be appreciated that battery  114  may be charged by removing battery  114  from vacuum cleaner  70  and placing it in a suitable charging unit. Preferably, battery  114  is charged in situ. To this end, vacuum cleaner  70  may include a plug  162  which is suitable for being received in a standard electrical outlet. Plug  162  is connected to circuit  112  by means of cord  164 . When plug  162  is withdrawn from receptacle  166  (which may be provided at any desired position in vacuum cleaner  70 ), mechanical lever  168  trips switch  132  so as to disconnect motor and fan blade assembly  98  from the current. In this way, motor and fan blade assembly  98  (FIG. 2) will still receive current from wires  136  and  138  thereby causing motor and fan blade assembly  98  to operate at low power during the recharging operation. 
     When plug  162  is removed from receptacle  166 , a signal is sent to microcontroller  116  such that when plug  162  is plugged into a standard power outlet, field effect transistor  128  is operated at, e.g. 60 KHz by microcontroller  116  while field effect transistor  120  provides low frequency pulses (eg. 10 Hz) to charge battery  114 . The frequency of operation of field effect transistor  128  can be raised or lowered to vary the output voltage used to charge battery  114 . 
     As will be appreciated, the operation of the motor and fan blade assembly  98  at low voltage DC during the recharging operation causes motor and fan blade assembly  98  to operate at a low speed so that air may be drawn across battery  114  and over, e.g., heat sink  170  which is thermally connected to battery  114  so as to cool battery  114  while it is being charged. 
     Optionally, a switch  132  may be arranged to disconnect wire  136  from motor and fan blade assembly  98  so that motor and fan blade assembly  98  will not operate during the charging mode. Rather, referring to FIG. 5, a separate cooling motor and fan assembly  99  may be provided in air flow communication near battery  114  to reduce the sensible temperature of battery  114  during charging. 
     As stated above, possible operating modes may include a “normal” operating mode, a “high flow” mode for auxiliary cleaning, a “standby” mode for reduced speed during interruptions in vacuuming, and a “battery recharge” mode. A vacuum cleaner according to the present invention may utilize any two of these operational modes in which case one switch is included for sending a signal to change between the modes. Preferably, the vacuum cleaner may be switched between any three of these modes (in which case the vacuum cleaner includes two switches) and, most preferably, the vacuum cleaner may be switched between all four modes (in which case it has three switches). It will be appreciated that the recharge mode is only applicable on battery operated vacuum cleaners. 
     The vacuum cleaner may use any switch or switches known in the art (e.g. mechanical or electrical; manual or automatic) and different operating modes may be actuated by different switches. Preferably the switches are constructed to automatically switch the current provided a motor when a user reconfigures the vacuum cleaner between, e.g., carpet cleaning and above the floor cleaning, when the vacuum cleaner is placed in the standby position or when a battery operated vacuum cleaner is recharged. However, switches which are manually operated by the user may be used to activate the various operating modes when the user reconfigures the vacuum cleaner. 
     It will be appreciated that the circuit of FIG. 1 is exemplary and that any power control circuit may be used to adjust the current provided to the motor.