AOpen DE7200 Series Instrucciones de operaciones descargar pdf (Pagina 12)

INTRODUCTION

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DE-7200VFDCentrifuge

pre-set torque limit is reached, the control system automatically reduces the feed rate to enable

the conveyor to clear the excess solids. When the centrifuge is operating at the reduced feed rate,

the Operation screen displays a message to inform the operator of the modified status. Unless the

over-torque condition is removed, the centrifuge will be shut down automatically.

Conveyor Drive Gearbox (Cont’d)

If a sudden overload torque condition occurs, the conveyor drive clutch mechanically disengages

the conveyor drive motor to protect the gearbox (Figure 1-3) from damage. Following

disengagement, the centrifuge must be shut down and the clutch manually reset as follows:

• Align both clutch halves at one of the marks on the actuation ring and body.

• Insert a screwdriver blade between the actuation ring and adjustment nut in two places 180°

apart, and press ring back into engagement position.

Disengagement Re-Engagement

Figure 1-3 Conveyor Drive Clutch Operating Principles

Drive Motors

The centrifuge is configured to operate on a designated AC voltage supplied in three-phase, 50Hz

or 60Hz. The machine is operated by two inverter-duty, three-phase, explosion-proof electric

motors. A 150HP bowl drive motor is connected to the bowl assembly by a sheave and series of

drive belts, while a 60HP electric motor is directly coupled to the gearbox input shaft by a clutch

coupling. A protective guard covers the sheaves, drive belts, and conveyor drive clutch coupling

for personnel protection.

Control Cabinet

All electric power distribution and control system components required for centrifuge operation are

installed in the control cabinet. Incoming power energizes the VFDs that supply the varying output

power for operation and control of the bowl, conveyor, and pump drive motors. A step-down

transformer adjusts incoming power to the 115 to 120Vac power required for operation of the PLC

and operator control panel. The transformer also energizes the 24Vdc power supply that produces

the required DC power for operation of control system components. An Ethernet communication

network permits two-way data transfer between the PLC, VFDs, and operator control panel.

The cabinet air conditioner maintains a suitable environment for efficient operation of the VFDs

and other power and control components. The air conditioner is a conventional refrigeration unit

consisting of a compressor, condenser, and evaporator. The PLC uses the temperature input

provided by an RTD sensor to cycle the air conditioner on and off as required to maintain the

interior temperature within a range of 85°F to 95°F (29°C to 35°C). When the temperature rises to

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AOpen DE7200 Series Instrucciones de operaciones Pagina 12