Electrical power required for the Conveyor is 480 volt, 3-phase, 60 hertz. For those facilities not equipped with such power, optional voltages are available upon request. The electrical equipment portion of the Conveyor operates on 480V, 3-phase, 60 hertz power except for the control circuitry which operates on 120 volt, single phase. All electrical components and materials used on the Conveyor conform to applicable NEMA (National Electrical Manufacturer's Association) standards and the requirements of the NEC (National Electrical Code) NFPA-70-84 and the American National Standards Institute Safety Code ANSI B20.1. All components are designed for continuous duty service.
ONLY QUALIFIED ELECTRICIANS SHOULD EVER WORK ON THE ELECTRICAL CIRCUIT. HIGH VOLTAGE IS DANGEROUS AND CAN CAUSE INJURY OR DEATH.
All electric wire and cable are color coded. The color code for power and control wiring from the load side of the circuit breaker to all other portions of the Conveyor is:
Power - Black
AC Control - Red
DC Control - Blue
Where practical, all electric wiring is enclosed in galvanized rigid steel conduit. Conduit is supported by clamps. Connecting leads to the motor are terminated in flexible liquid tight metallic conduit. All fittings are liquid tight, of the same manufacture as the flexible conduit, and in accordance with Federal Specification W-F-406.
The conveyor is provided with a 3-pole molded case circuit breaker connected in the power circuit. The Master Control Panel door is mechanically interlocked with the circuit breaker by means of an external operating mechanism to ensure that it can be opened only when the breaker is in the open position. This mechanism has padlocking provisions only in the "OFF" position.
The motor starters consist of three-pole, single-throw, magnetic starters, each with a hold-in contact and auxiliary contacts as required. The motor starters have manual reset overload relays with electrical and mechanical interlocks. The Conveyor may be provided with a three position motor reversing switch to provide for a change in the Conveyor's mode of operation. The belt switch positions are labeled "FORWARD" and "REVERSE".
The motors used on the Conveyor operate on 480 volt, 3-phase, 60 hertz power or as specified. All motor leads terminate in a connection box mounted on the housing. All motor leads are properly identified according to NEMA standards and the motors will operate satisfactorily on a voltage 10 percent above or below the normal operating voltage.
The gear drive units are foot mounted to provide maximum rigidity of the unit. The gear drives are lubricated by the oil bath method of lubrication and the oil seals totally retain the gear and bearing lubricants. Breather plugs, that prevent dirt from entering the gear drive, are also provided. The basic design of the gear drive is such that the operating temperature of the oil sump will not exceed 200 degrees F. The units also typically have the following features:
Self-lubricated splined coupling allows removal of rotor without disturbing gearing. Two double-lip oil seals in tandem at output shaft provides four sealing surfaces. Forged "LMS" bronze worm wheel provides extra strength, extra life, and extra smooth surface. Short peened shaft seal area provides miniature reservoirs of oil, to keep seal lubricated. Roller bearings on output shaft provide ample rating for high overhung loads.
The motor brakes used on the boom, traverse, decline-incline or any other location on the conveyor are integrated with the respective drive motor. The brakes are the spring set solenoid release type and incorporate manual adjustment of friction surfaces that are necessitated by wear. See brake cover for adjustment information.
The primary winding of the control transformer is wound for 460 volt supply voltage or as specified with a single isolated secondary winding of 120 volts. One side of the secondary winding is grounded in accordance with the National Electrical Code. The control circuit transformer is mounted in the Master Control Panel.
A multi-conductor flexible cable provides the connection for the power and controls required on the telescoping boom sections. A spring driven reel is used to provide power to the front of the conveyor. This reel is normally mounted under the conveyor. The cable is guided through roller brackets under the booms on its approximate centerline. The cable is terminated in a fixed junction box on the front of the conveyor. Cable tension is removed from the conductors by the use of a steel cable grip.
The entire electric conduit and wiring systems, conveyor structures and supports are grounded to protect personnel from possible shock.