9
Check the SCR snubber card
Instruction manual
IM1002004E September 2015 www.powerquality.eaton.com
Figure 3. SCR tester
6. Re-assemble the power module assembly, make sure
all connections are tight.
WARNING
Do not connect the semi-conductor fuse, wires or fan
wires at this point.
Check the SCR snubber card
1. Three components make up the SCR snubber—
resistors, MOVs, and capacitors. Check for open
resistors. Check MOVs for shorts, they should read
high resistance when ohmmeter is placed across them.
Resistance check each capacitor. The DC resistance
across the snubber capacitor-should look capacitive-
that is high resistance after the meter charges the
capacitor. If it measures open or shorted, replace the
snubber card.
2.
RE-CONNECT SEMI-CONDUCTOR FUSE, ALL
WIRES, AND FANS. DOUBLE CHECK THAT ALL
CONNECTIONS ARE SECURE.
otes:
N
Control board # 49120 is for 10 kVA to 50 kVA units.
Control board # 407415 is for 75 kVA and larger.
WARNING
Do not connect TB1, TB2, and TB3 connectors from the
control cards #49120/407415 yet.
Check control card and filter card
1. Verify input to the conditioner matches the unit’s
specification. Also verify correct control board
#49120/407415 jumper setup on
page 21
.
2. Disable the over/undervoltage shutdown card #35867
(optional card) by removing connectors K1 and K2 on
the card.
3. Turn on AC input breaker to unit.
IMPORTANT
Extreme caution must be taken when measuring voltages
on Molex connectors. Do not press meter leads into
connectors or bend connectors back.
4. Measure the following voltages on wires feeding
the TB1 Molex connector to the control card on all
three phases.
Pins 1 and 3 = 4–6 Vac.
otes:
N
When the connector is plugged in, this voltage is
around 3 Vac.
Pins 7 and 8 = 120 Vac
If this voltage is incorrect or not present, then check
the fuses associated with the filter card or replace filter
card and re-check voltages.
5. Turn main AC circuit breaker off. Plug in connectors TB1
and TB3 only. On the control card #49120 / 407415 on
all three phases.
6. Turn main AC on. With DC voltmeter on the millivolt
scale, check between TP1 and TP GND of the control
card and adjust pot P2 so meter reads “0” millivolts or
close as possible.
otes:
N
This step does not apply to control board # 407415.
otes:
N
Refer to
page 21
for test points and pot locations
on control card.
7. Use the following formula to calculate the next
adjustments. You must calculate each input phase for
each control card or a total of three calculations.
a. For phase 1 control card, measure AC input at Line 1
to Line 2.
b. For phase 2 control card, measure AC input at Line 2
to Line 3.
c. For phase 3 control card, measure AC input at Line 1
to Line 3.
Formula
AC Input x 2.47 = Volts DC at TP2
480 (Nominal)
Example
475 Volts AC Input x 2.47 = 2.44 Volts DC at TP2
480 (Nominal)
1K
Ω
1 Watt
Switch 1
