Howard Industries
®
voltage regulator application
The replacement procedure may be performed in the shop
or the field. The regulator must be bypassed or removed
from service prior to installing the CRA kit. Always bypass
the regulator when installing the CRA kit in the field to
prevent opening the CT circuit while the regulator is under
load.
1. Bypass the regulator or remove it from service.
2. Open the existing control box and swing out the control
front panel. Remove the front panel by disconnecting
the jack plug and lifting the control off of its hinges.
3. If the incoming control cable leads are not marked or
color-coded, place appropriate wire markers on the
control cable leads and mark for reference later.
4. Disconnect the incoming control cable leads from the
female jack plug located on the back of the control box.
If the tap-changer motor capacitor is located in the
control box, disconnect the leads from the capacitor
and remove the capacitor for reinstallation in the new
box.
5. Remove the incoming control cable-retaining nut and
remove the cable from the control box.
6. Remove the cable compression connector (cable grip)
from the control box.
7. Remove the nameplate from the old control box assem-
bly and retain, with the hardware.
8. With an adjustable wrench or appropriate socket
wrench, remove and retain the bolts holding the control
box on the regulator and remove the old control box
assembly from the regulator.
9. Place the supplied universal bracket over the control
cabinet mounting bosses on the regulator and secure it
with bolts retained in Step 8.
10. Place the CRA control box on the universal bracket and
secure it to the regulator using hardware provided.
11. Attach the nameplate to the front of the CRA control
box with hardware retained in Step 7.
12. Ground the control cabinet using the ground boss
located on the side of the cabinet.
13. Examine the control cable. Allow approximately 12" of
lead length to protrude past the end of the conduit nut.
This will facilitate connection to the top terminal strip
and knife switches located in the control box.
14. Remove the cable grip nut and rubber cable grommet
from the cable entrance of the new control box.
15. Place the cable grip nut over the existing control cable.
Select one of the two supplied cable grommets that
best fits the existing cable; place grommet onto the
control cable.
16. If the motor capacitor was located in the old control
box, do not cut the terminals from the capacitor wires.
Cut all other terminals from the end of the cable
conductors.
17. Strip the insulation back approximately 5/16 of an inch
on each lead to be connected in the new control box.
18. Insert the control cable into the control-box cable grip
connector, seat the rubber grommet, and tighten the
cable grip nut.
19. V6 connections and source-side PT input:
A.
If there is no source-side PT input, or if there is a
source-side PT input, but the source-side voltage is
to be calculated by the control, the control box has
been pre-configured for this type of operation; no
further action is required.
B.
If the regulator has a source-side PT input present
and it will be used to supply a source-side voltage
for reverse operation, take the following steps:
i.
Connect the Howard MS lead to the top of
the V6 switch.
ii.
Using the supplied tool, remove the white/
brown number 23 lead from the bottom
section of V1 and place it at the bottom of V6.
20. Connect remaining leads per Table 3 and Figures 10 and
11.
21. If the motor capacitor had been located in the old
control box, install and reconnect it in the CRA control
box and secure the capacitor.
DANGER
Explosion Hazard. Voltage regulators are subject to
high circulating current during bypass switching.
Refer to
Service Information MN225003EN CL-7
Voltage Regulator Control Installation, Operation, and
Maintenance Instructions
for information on the CRA
Control, and refer to the instruction manual supplied by
the voltage regulator manufacturer for specific safety
procedures for bypass switching. Failure to comply will
result in severe personal injury or death.
VR-T214.0
WARNING
Hazardous Voltage. The control box must be solidly
earth grounded. Failure to comply can result in severe
personal injury and equipment damage.
VR-T216.0
DANGER
Flashover Hazard. Opening the CT circuit under load
will produce high voltages in the control box. Always
bypass the regulator when installing the CRA to
prevent opening the CT circuit while the regulator is
under load. Failure to comply n result in severe personal
injury or death.
VR-T215.0
12
CL-7 control replacement assembly installation instructions and service information
MN225017EN October 2016
