FUZZBLUE.jpg (23434 bytes)FLOMATCHER/MARATHON

SPECIALISTS IN VARIABLE SPEED MOTOR CONTROL SYSTEMS

Pacesetter

DC ADJUSTBLE SPEED DRIVES

PACESETTER RELIABILITY - Marathon Electronics adjustable speed drives combine simplicity and low cost with proven performance and reliability. All critical components are conservatively rated and tested under severe conditions before assembly. The entire drive system is then thoroughly tested again prior to shipment. A wide selection of optional features is available to fit most general purpose and heavy duty applications.

CONTROLLER - The controller features a rugged full wave silicon controlled rectifier bridge, which efficiently transfers power from the AC line to the motor while minimizing motor heating. Safety features of the controller include an enclosed cabinet, a door interlocked circuit breaker, and grounded low voltage (120V AC) control circuitry. The controller includes circuitry to protect against motor overload conditions or line overvoltage transients.

The current feedback signal is obtained by use of a current transformer on each of the three incoming lines. The signals from these transformers are thereby electronically isolated from the line voltage. The output (armature) voltage feedback signal is detected through a high impedance circuit thus reducing the electrical hazard. The firing pulses are connected to the SCR's through isolating pulse transformers. In addition, the regulator circuits and reference signals are referenced to chassis ground and are not allowed to float. LED (light emitting diode) indicators glow to verify drive operation or the existence of a fault condition.

 

The regulator is multi-loop, utilizing integrated circuits for fast response with good stability. The speed regulator loop utilizes either armature voltage feedback or tachometer signal feedback for fast dynamic response. The inner loop current limit provides precise current limiting with inherent stability.

 

MODULAR CONSTRUCTION - The regulator module, containing all of the regulator and logic components, is a plug-in printed circuit board. The application adjustments are located on a programming module which plugs into the regulator module. In the event servicing of the regulator module is required, the programming module is removed, the regulator module is replaced, and the programming module is reinstalled in the new regulator module. No adjustments are necessary as all adjustments are contained on the programming module. This can be accomplished in a matter of minutes with great savings in costly downtime.

SPECIFICATIONS - The following data is applicable to the controller only. The motor characteristics must be taken into account when considering the complete system.

EFFICIENCY: Approximately 97% at rated output.

OVERLOAD CAPABILITY: 150% for 60 seconds via an inverse time trip.

SERVICE FACTOR: 1.0

SPEED RANGE: 20:1 with voltage feedback.

STANDARD CONTROL FEATURES

Series 4310 Non-Regenerative-Full wave, three phase rectification (six controlled legs) gives better wave-form and less motor heating.

Series 4320 Regenerative-Six controlled legs for each direction of rotation gives regenerative braking and reversing without contactors.

Totally enclosed cabinets with external heatsinks through 150 HP at 500v DC.

Personnel safety features include:

Circuit breaker, door interlocked.

Current feedback isolated from line voltage.

Voltage feedback isolated from line through high impedance.

Chassis grounded regulator common.

Chassis grounded 120V AC control circuits.

Protective Functions:

AC current limiting fuses protect SCR's against fault currents.

Snubber network transient protection for SCR's.

Undervoltage and phase loss protection.

electronic instantaneous and inverse time overload protection.

Control is insensitive to incoming line phase rotation.

Thermostat for blower cooled heat sinks.

Field loss protection

Field economy circuit reduces field excitation to 67% voltage during idle periods for extended insulation life.

LED's indicate RUN and FAULT status.

Maintenance is simplified with modular construction:

Drive power module includes control interconnections and protective circuits.

Regulator is easily replaced without disturbing set-up adjustments.

Plug-in programming module provides adjustments for:

Maximum Speed

Minimum speed

Linear accel/decel (rates independently adjustable 2-20 sec.)

Current limit 0-150%, factory set for 150%

Response (stability)

IR compensation (for voltage feedback units only)

COMMON OPTIONS

Special enclosures

Special operator stations

Isolation transformer

Circuit checker

DC loop contactor

Dynamic braking

Contactor reversing

Preset jog speed

Starter for motor blower

Tach feedback

VERSATILITY - DC drives are the most versatile of all the adjustable speed drive types.

 

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Last modified: June 19, 1998