Silicon Controlled Rectifier Specification Sheet

Hubbell Industrial Controls, Inc.
S
2
MC Compact Primary Thyristor Controller 4922C
For Hoists Without Mechanical Or Eddy Current Brakes
Catalog 4922C • May 1993
Page 1 of 2
General
The Type 4922C S
2
MC primary thyristor static
reversing controller system provides speed-regulated con-
trol of hoist with wound rotor motors and without load
brakes. The Type 4922C system includes the controller
and for separate mounting the Type 5410 tachome-
ter/overspeed switch assembly and Type 3000 secondary
resistor.
The operator control is a Type 4216 stepless mill
master switch. Type 4211 stepless mini master switch or
Type 2015/6/7 stepless pendant pushbutton station. Full
range of motor speed from minimum to maximum is ad-
justed by the stepless operator. Hoisting speed, with or
without load, is closely controlled by varying the motor pri-
mary voltage with thyristors. No-load lowering speed is
handled in the same manner. Lowering speed of an over-
hauling load at subsynchronous speeds is controlled via
counter-torque control.
4922C controllers are available from 10 to 250 HP
at 460/3/60 VAC.
Operation
Hoisting: When the hoisting direction is selected,
the M contactor closes and hoisting torque is produced by
the motor when selected primary thyristor modules begin
conduction. The amount of thyristor modules begin con-
duction. The amount of thyristor conduction and hence,
motor hoisting torque, is determined by the master switch
speed reference signal and the tachometer speed feedback
signal. In this manner, stepless adjustable speed control is
obtained for hoisting.
Lowering: When the lowering direction is se-
lected, the M contactor closes and the selected primary
thyristor modules begin conduction.
If the hook is empty or lightly loaded, the controller
will maintain the motor in a stepless speed regulated "driv-
ing lower" condition.
If the load overhauls the motor, the controller will
turn off (2) of the thyristor modules and turn on the other (2)
thyristor modules. This transition converts the motor op-
eration from a driving lower condition to a counter-torque
condition with hoisting torque controlling the descending
overhauling load in a controlled stepless manner.
As full speed is reached, the controller reverts
back to a drive down mode and the motor is placed into
regeneration. When leaving the regenerative lowering
mode, the controller reverts back to counter-torque lower-
ing.
Features
The Type 4922C standard controller includes the
following major components/features:
S
2
MC Compact Variable Speed Control As-
sembly consisting of (1) regulator PC board and (2) firing
circuit board. All adjustments, potentiometers, and test
points for setup and fine-tuning plus status lights are front-
panel-mounted and clearly identified. Simple test setup
readings require use only of a VOM meter.
Five (5) conservatively rated Type 5410 Full
Wave Thyristor Power Modules with MOV transient volt-
age protection and snubbing circuits to limit rate of voltage
rise. Thyristor modules for 40HP/460 volt and under are
mounted with the S
2
MC Compact Speed Regulator Assem-
bly. Over 40HP the thyristor modules are separate mount
within the controller enclosure.
S
2
MC Tachometer Continuity Module monitors
the tachometer feedback signal and shuts down the con-
troller in the event of an open tachometer signal.
In addition to the S
2
MC modules the Type 4922C
controller features a three-pole main knife switch. NEMA
rated mainline contactor, (3) Inverse time trip overload re-
lays, fused control knife switch, 120 volt control trans-
former, low voltage relay and a shunt brake relay.
Optional Features
Full Speed Contactor: The 4945C hoist system
requires a secondary slip resistor to provide optimum
torque at reduced speeds, but results in a 20% slip at full
load/full speed. The full speed contactor shorts out this
resistor at high speed and allows the motor to obtain its
maximum rated base speed.
Extended Slow Speed Operation: This option
allows the hoist to operate at reduced speeds for an ex-
tended period of time. Recommended for die handling
cranes and turbine handling cranes.
Five Step Reference Board: This option allows
the controller to operate from a standard 5 step sequential
master switch or pendant. Each step can be independently
set for a fixed speed.
Multi-panel Construction: This option provides
two or more controllers to be mounted in a common enclo-
sure and interwired with a mainline contactor panel.
Other standard modifications and options are
available. Consult factory for assistance.