Tweco Troubleshooting Power Supply - Manual (Page 6)

6
• If T1 measures OK, check for shorted capacitors C1-C3.
3. No 120 VAC to T1 primary during the ignition phase (15 seconds following
Preflow) check for 120 VAC into the line filter. It it’s there replace the filter.
If not present go to step 4.
4. CCM sends signal HF Enable (active low) at J35-10 to CN10-10 (other end
of ribbon cable) on power supply board WK-5602 (PCB5). Signal leaves
PCB5, still active low, on CN8-4 and goes to CN8-4 of relay board WK-5628
(PCB7) closing relay RY5. 120 VAC from T1 passes through rear panel
circuit breaker CP2 to PCB7’s CN6-1 & 4. RY5 contacts closed sends this
120VAC out on CN7-1 & 4 to rear panel RAS connector J59-7 & 9 to turn on
the Arcstarter (RAS or GCM1000).
T1 Assembly
Line Filter 1ph
Line1
Line2
Load1
Load2
GND
T1
1
2
3
4
R1 6.8K 1W
R2 6.8K 1W
Ultracut / Autocut
RAS 1000
J58-RAS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
T1
TX1P8S
460
220 0___
120.
0___
C.P2
AC120V @ 1A
CN7
1
2
3
4
RY5
0V RAS
AC120-RAS
CN6
1
2
3
4
Part of PCB7
WK-5628
Relay PCB
J59-RAS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
KEY PLUG
Pilot Regulator (chopper) Power
Chopper module bias power is high DC voltage supplied to CN5 on the larger
of the two chopper PCBs. For all power supplies except 600V, bias power for
the chopper comes from P1 (white wire) and N2 (black wire) from top inverter
module PCB9 (WK-5605). Voltage will be around 600-700VDC for 400 & 460V
inputs and 300-350VDC for 208-230 volt input.
For 600V power supplies the chopper bias comes from a diode D3 mounted to
the rear of the T1 transformer. Power to D3 comes from the T1’s 200 VAC
primary.
Pilot Enable & Pilot Demand
As soon as CNC Start is applied, CCM makes signal Pilot Enable true (active
low) on J35-9. /Pilot Enable goes to PCB5 (WK-5602A) CN10-9 where it turns
on relay RY1. 110 VAC from T1 goes to CN9-1. RY1 connects the 110 VAC to
CN9-5 to turn on the pilot contactor.
For Chopper Pilot units /Pilot Enable from PCB5 is sent to the Chopper module
on CN33-2 (CN33-4 common) to CN2-2 to turn on the chopper. Signal is high,
about +15 VDC when not enabled and goes low, nearly zero volts to enable the
chopper.