GE VALUTROL MAIN CONTROL MODULE Instructions Manual page 26

GEK·24994
Monitor DR and turn
CUR liMIT
CCW until DR ju"t moves
away from zero
IMET
(load instrument calibration)
Turn the
CUR REF
until CFB corresponds to full load
current. Verify that the optional load instrument reads full
load. If not, remove power, adjust
IMET
and repeat.
liN TIME
(linear time)
Monitor TR and set to zero with the
LOt REF.
Rapidly turn
the
lOCREFfull
Fwd and measure the time for TR to ramp to
10 volts (±10%).
Adjust
liN TIME
until thIS time
corre!>ponds to the test data sheet linear time.
Set the
lOC REF
to the center position and sWItch to
Diagnostic Run.
MAX SPEED
(maximum speed)
Adjust the
lOO REF
until the motor is running at actual top
speed. Adjust
MAX SPEED
until SFB is 10 volts (±10%).
OEMF liMIT
(counter emf limit)
Turn
OEMF liMIT
full CCW and turn the
LOO REF
full Fwd.
Adjust
OEMF liMIT
until CEMF corresponds to the CEMF
LIMIT on the test data sheet.
SMET
(speed Instrument calibration)
Turn the
LOC REF
potentIOmeter until SFB IS
3
volts (±1O%).
The optIOnal speed indicator should indicate 30% top
speed. If it does not, push the RESET button to mitiate a
shut down. Remove power, adjust
SMET
and repeat.
Return the DIagnostic switch to Normal.
REF SCALE
(reference scale)
Turn
REF SCALE
full CCW. Start the drive and apply top
speed reference to SR. Adjust the
REF SCALE
potentIOmeter
until SFB is 10 volts (±10%). This normalizes the timed
reference TR and speed feedback. SFB for 10 volts(±lO%)at
top speed.
MIN SPEED
(minimum speed)
Reduce the system reference to minimum and start the
drive. Adjust
MIN SPEED
as required to meet system
minimum speed reqUIrements. Refer to system elementary
diagram for circuit details.
RSTOP
(regenerative stop)
With the motor operatmg at some RPM. call for a drive stop
by mitiating the proper magnetics which will release 2TB·
14 from -30 volt!>. The motor will decelerate to zero speed
and the contactor will open. If the contactor opens before
the drive comes down to a stop,
RSTOP
IS set too far CWo If
the contactor fails to open,
RSTOPis
set too farCCW. Push
26
the RESET button to drop out the contact or prior to
removmg power.
RSTOP
should be adjusted with power
removed.
"AIN, RESPONSE, DAMP,
and
COMP
(Stability
adjustments)
1.
Set
DAMP
potentIOmeter at minimum 7 a 'clock
posItion.
2.
Place the DiagnostIc switch in the static mode. Adjust
OIJR REF
for 2.5 volts at test pin eFB. This is
equivalent to rated armature current.
3. Set
COMP
potentiometer by reading at the CEMF test
pin a value equal to 0.0312 (240V - motor CEMF)
for 240V drives. For 500V drives use .OJ48 (500V -
motor CEMF).
Typical values of motor counter EMF:
MOTOR MOTOR
HORSEPOWER COUNTER EMF
240V 500V
5 to 15 215 455
20 to 40 225 470
50 to 125 230 480
150 to 250 490
The reading at CEMF test pin is a voltage proportional to
motor CEMF.
Example: 20 to 40 HP @ 240V
CEMF " 0.0312 (240 - 225)
:: 0.468 volts
The
COMP
potentiometer is now set for proper operation.
Regardless of overload range of IOC setting is correct and
should not be changed.
4. Set the
CAIN
adjustment to minimum 7 o'clock
position.
5. Set
LIN TIME
potentiometer at mimmum 7 o'clock
position.
6. Set
RESPONSE
potentiometer at mmimum 7 o'clock
position.
When the drive IS functioning properly in all other
respects make small incremental step increases in
speed. Observe armature current for bumping
repeatedly before steady state !i>peed is attained,
Increase the
RESPONSE
settmg (move CW) until
bumpy current is observed. Then reduce the
RESPONSE
setting until no bumps (or only one)
IS
observed. ThIS IS the maXImum
RESPONSE
setting.