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                                     ELECTRIC HOIST

                                                                                                   Series Wound Motor

 

This Liftmoore crane features an electrically driven planetary gear hoist.  The hoist is powered in both directions and features an automatic internal brake to positively control the load.  It is permanently lubricated.

Motor

The hoist motor is a direct current (DC), reversible motor. It is Series Wound – the field coils (terminals F1 & F2) and armature (terminal A) must be connected in series.  The fourth, unmarked terminal is ground.

Caution! The hoist motor is rated for intermittent duty.  Duty cycle is limited to 5 minutes in 30 to allow the motor to cool.  Extended use can damage the motor and brake.

Thermal switch

The motor incorporates a normally closed thermal switch to help prevent damage.  When the motor heats up the switch will open, preventing hoist up.  When the motor cools, the switch will close automatically.

Caution! When the thermal switch opens, hoist down will continue to function, but will continue to build heat.  If the load cannot be safely lowered quickly, discontinue use until the motor cools.  Motor and brake damage may result.

Brake

The hoist features a single acting, overrunning brake.  It automatically activates to hold the load and assist in lowering the load.

Warning! Overheating the brake may result in permanent damage and possible failure of the brake.  Replace any damaged components before continuing use.

Warning! The hoist brake only functions in one direction.  If the hoisting direction is reversed by reversing the rope winding direction the brake will not hold and the load will fall.  Serious injury or death could result.

The brake is factory set and is not adjustable.  If the brake fails to hold the load or if downward drift becomes excessive the brake must be replaced.

Caution! Never reverse the motor while it is spinning, allow the motor to come to a complete stop before changing direction. Rapid reversal will damage the winch motor.

Directional Control

A sealed contactor that incorporates three double pole-double throw relays controls motor direction.  The contactor allows for directional control and provides dynamic braking in the neutral position.

The power, ground, and motor wires are connected to the top bolted terminals, which are clearly labeled.  Signal wires are connected to the 3 male spade disconnect terminals on the front of the contactor.

Signal voltage, controlled by the pendant, energizes the applicable relays and controls the direction of the current flow through the field windings, F1 & F2, then directs current though the armature, A.

When the DOWN (right) terminal is energized, current flows from motor terminal F1 to F2, then to A.  Energizing the UP (Left) terminal directs current from F2 to F1, then to A.  The center terminal is the ground for UP coil.  The DOWN coil is internally grounded.