Over current protective circuit with time delay for a floor cleaning machine

Circuit for controlling the operation of a first motor and a second motor, said first motor having a first starting current value, said second motor having a second starting current value, said second starting current value being less than said first starting current value, comprising, in combination:

• first switch means operatively coupled to first relay means for energizing said first motor;
• second switch means operatively coupled to second relay means for energizing said second motor;
• 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 for enabling said second motor when a first period of time from said first time has elapsed;
• and means for restoring operation of said second motor after said first period of time has elapsed, if said second motor was operating at said first time.

Circuit for controlling the operation of a first motor coupled to an agitating means, said first motor having a load adjustment means, a starting current value, and a load current value, 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;
• 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 first period of time during which said load current value has continuously exceeded said first reference current value has elapsed;
• means for operating said first relay means to disconnect said power source from said first motor if said load current value exceeds a second reference current value;
• and means for providing an overload indication to an operator when said load current exceeds said first reference current value to allow adjustment of said load adjustment means to reduce said load current value within the first period of time.

A method of operating 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, said second motor having a second starting current value, said second starting current value being less than said first starting current value, comprising the following steps:

• disabling operation of said second motor during a first motor start up period;
• restoring operation of said second motor if said second motor was operating prior to said first motor start up
• obtaining a first signal representative of said first motor load current value;
• comparing said first signal to a first level overload reference signal and to a second level overload reference signal;
• timing a duration of a first level overload condition;
• disabling operation of said second motor if said duration exceeds a first period of time;
• and
• disabling operation of said first motor if said first signal exceeds a second level overload reference signal.

A method of operating a motor coupled to an agitating means, said motor having a load current value, comprising the following steps:

• obtaining a first signal representative of said motor load current value;
• comparing said first signal to a first level overload reference signal and to a second level overload reference signal;
• timing a duration of a first level overload condition;
• disabling operation of said motor if said duration exceeds a first period of time;
• and
• disabling operation of said motor if said first signal exceeds the second level overload reference signal, wherein said motor has a load adjustment means and said step of comparing said first signal to a first level overload reference signal and to a second level overload reference signal includes providing an overload indication to an operator when said load current value exceeds said first reference current value to allow adjustment of said lead adjustment means to reduce said load current value.

A method of operating a tint motor coupled to an agitating means, and a second motor for use in creating an air flow, said first motor having a starting current value greater than a starting current value of said second motor, comprising the following steps:

• operating said second motor while the first motor is not operating;
• disabling operation of said second motor during a first motor start up period;
• starting said first motor during the first motor start up period;
• and
• restoring operation of said second motor after the first motor start up period and while the first motor is operating.