초록 ▼

A protective circuit controls the operation of a floor cleaning machine provided with a brush motor and a vacuum motor. The protective circuit disables the vacuum motor when an operator starts the brush motor and then restarts the vacuum motor provided it was previously running. The floor cleaning m

A protective circuit controls the operation of a floor cleaning machine provided with a brush motor and a vacuum motor. The protective circuit disables the vacuum motor when an operator starts the brush motor and then restarts the vacuum motor provided it was previously running. The floor cleaning machine is also provided with provisions for adjusting the action of the brush and thus changing the load current of the brush motor. The load current of the brush motor is continuously compared to a first level overload current and an indicator alerts the operator to a first level overload condition allowing a predetermined time for the load current to be reduced by adjusting the brush. If the load current is not reduced, then the brush motor is de-energized. If a second level overload condition of the brush motor occurs at any time, the brush motor is de-energized immediately.

대표청구항 ▼

Circuit for controlling the operation of a first motor coupled to an agitating means and a second motor for creating air flow, said first motor having a first starting current value, a load current value and a load adjustment means, comprising, in combination: first relay means for controlling the a

Circuit for controlling the operation of a first motor coupled to an agitating means and a second motor for creating air flow, said first motor having a first starting current value, a load current value and a load adjustment means, comprising, in combination: first relay means for controlling the application of an electrical power source to said first motor; first switch means coupled to said first relay means; second relay means for controlling the application of said electrical power source to said second motor; second switch means coupled to said second relay means; means operatively coupled to said first switch means and to said second relay means for disabling said second motor when said first switch means is activated at a first time and to enable said second motor when a first period of time from said first time has elapsed; means for obtaining a first signal representative of said load current value; first means for comparing said first signal to a first reference current value; means for operating said first relay means to disconnect said power source from said first motor if a second period of time during which said load current value has continuously exceeded said first reference current value has elapsed; and means for operating said first relay means to disconnect said power source from said first motor if said load current value exceeds said second reference current value.