Cornelius Series 725 Electrical Circuit, On-Off Switch/Circuit Breaker, Bin Thermostat

Self-Contained Flaked Ice Maker Service Manual

ELECTRICAL CIRCUIT

CIRCUIT DESCRIPTION

As the manual on-off circuit breaker switch is pushed to ”on”, an electrical circuit is completed to the gearmotor via the circuit breaker gearmotor overload, power relay/contactor, gearmotor delay thermostat and the bin thermostat. After the previous circuit has been completed the condenser fan motor will start as will the compressor (via the high pressure control, the compressor starting relay and low ambient control).

On-Off Switch/Circuit Breaker

This switch interrupts power to the entire unit. The switch has a circuit breaker incorporated into its’ design. This circuit breaker will trip out in the event the gearmotor draws to high of amps. In such an event the power is interrupted to the unit. To reset the circuit breaker and reestablish power to the unit, push the switch to the “off” position and then back to the “on” position.

Bin Thermostat

This is electrically in ”series” with the ice making system. When the bin is full, the contact opens, terminating power to the machine.

High Pressure Control

Switch contact will open at 450 PSI for R404a breaking the circuit to the compressor. This control is manually re-settable.

Gearmotor Start Relay

This is a current type relay which means as the gearmotor run winding comes ”on” the line, the current draw initially is relatively heavy through the relay coil (coil is in series with run winding). It then acts like a normal relay and the N.O. start contact ”makes”, completing a circuit through the start capacitor to the start winding. As the gearmotor picks up speed, the amp draw through the relay coil drops off allowing the armature to return to its normal position (start contact ”opens”). This action removes the start winding from the circuit.

Power Relay/Contactor

This relay controls the compressor power only.

Fan Cycling Switch

The function of this switch is to maintain condensing pressures at a satisfactory level during-low ambient conditions. The switch breaks the circuit to the condenser fan motor at 205 PSI and makes the circuit at 275 PSI.

Delay Thermostat

This thermostat keeps the gearmotor running until the suction line temperature reaches 45° after the full bin switch terminates power to the power relay.

Compressor Start Relay

This is a current type relay and contains a N.O. contact which is connected in series with the start winding of the compressor. The relay coil is electrically in series with the run winding. When power is applied, the compressor draws high current which sets up a magnetic field in the magnet coil which causes the relay to operate, closing the relay contact. As the compressor approaches operating speed, the current flowing through the coil decreases, permitting the relay contact to open, thereby opening the starting circuit.

© 2004, IMI Cornelius Inc. - 7 - Publication Number: 166240010SER