BENSHAW RediStart MX3 Series, User Manual

Page: 98 / 238

Description When the Stop Mode (CFN15) is set to "DC brake", the DC Brake Delay time is the time delay between when
a stop is commanded and the DC braking current is applied to the motor. This delay allows the residual
magnetic field and motor counter EMF to decay before applying the DC braking current. If a large surge of
current is detected when DC braking is first engaged increase the delay time. If the delay before the braking
action begins is too long then decrease the delay time. In general, low horsepower motors can utilize shorter
delays while large horsepower motor may require longer delays.
See Also Stop Mode parameter (CFN15) on page 85.
DC Brake Level parameter (CFN20) on page 88.
DC Brake Time parameter (CFN21) on page 89.
Theory of Operation section 7.5.9, DC Injection Braking Control, on page 164.
Preset Slow Speed CFN 23
LCD Display
Range
Off, 1.0% – 40.0 %
(Default Off)
Description
The Preset Slow Speed parameter sets the speed of motor operation. When set to "Off", slow speed operation
is disabled.
Slow speed operation is commanded by programming one of the digital inputs to either Slow Speed Forward
or Slow Speed Reverse. Energizing the Slow Speed Input when the starter is idle will initiate slow speed
operation.
z
NOTE: When the motor is operating at slow speeds its cooling capacity can be greatly reduced. Therefore,
the running time of the motor at a given current level is dependant on the motor’s thermal capacity. Although
the Motor OL is active (if not set to "Off") during slow speed operation, it is recommended that the motor
temperature be monitored when slow speed is used for long periods of time.
See Also
Slow Speed Current Level parameter (CFN24) on page 90.
Slow Speed Time Limit parameter (CFN25) on page 94.
Motor PTC Trip Time (PFN27) on page 104.
Digital Input Configuration parameters (I/O 01 - 08) on page 111.
Relay Output Configuration parameter (I/O 10 - 15) on page 112.
Theory of Operation section 7.6, Slow Speed Operation on page 164.
Preset Slow Speed Current Level CFN 24
LCD Display
Range 10 – 400 % FLA (Default 100%)
Description The Preset Slow Speed Current Level parameter selects the level of current applied to the motor during slow
speed operation. The parameter is set as a percentage of motor full load amps (FLA). This value should be
set to the lowest possible current level that will properly operate the motor.
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NOTE: When the motor is operating at slow speeds its cooling capacity can be greatly reduced. Therefore,
the running time of the motor at a given current level is dependant on the motor’s thermal capacity. Although
the Motor OL is active (if not set to "Off") during slow speed operation, it is recommended that the motor
temperature be monitored when slow speed is used for long periods of time.
See Also Motor Running Overload Class parameter (QST03) on page 73.
Slow Speed Time Limit parameter (CFN25) on page 94.
Motor PTC Trip Time (PFN27) on page 104.
Theory of Operation section 7.6 , Slow Speed Operation on page 164.
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6 - PARAMETER DESCRIPTION
CFN: SSpd Speed
23
Off
CFN: SSpd Curr
24
100%