121
NOTE: Both SCRs may be defective, but typically, only
one is shorted. If both SCRs provide acceptable resistance
measurements, proceed to Step 10.
8. Replace the defective SCR(s).
9. Retest the “pair” for resistance values indicated above.
10. On the right side of the firing card, measure the resistance
between the red and white gate/cathode leads for each
SCR (1 through 6). A measurement between 5 and
50 ohms is normal. Abnormally high values may indicate
a failed gate for that SCR.
11. Replace the SCRs and retest the pair.
SCR REMOVAL/INSTALLATION
1. Remove the SCR by loosening the clamping bolts on
each side of the SCR.
2. After the SCR has been removed and the bus work is
loose, apply a thin coat of either silicon based thermal
joint compound or a joint compound for aluminum or
copper wire connections to the contact surfaces of the re-
placement SCR. This allows for improved heat dissipa-
tion and electrical conductivity.
3. Place the SCR between the roll pins on the heat sink
assemblies so the roll pins fit into the small holes in each
side of the SCR.
NOTE: Ensure the SCR is installed so the cathode side is
the side from which the red wire extends. The heatsink is
labeled to show the correct orientation.
4. Finger tighten the clamp. Ensure both bolts are tightened
an equal amount so that the loader bar is square in the
heatsink. See Fig. 57.
5. Tighten the bolts equally in
1
/
8
turn increments until the
indicator washer(s), which are under the nut(s) in the
center of the loader bar becomes loose indicating that the
clamp is tight. See Fig. 57. On the loader bars with two
indicator washers, it may be necessary to tighten or loos-
en one side of the clamp to get both indicator washers
free. Reconnect the red (cathode) wire from the SCR and
the white (anode-gate) wire to the appropriate location on
the firing card (i.e., SCR1 wires to firing card terminal
G1-white wire, and K1-red wire).
6. Reconnect all other wiring and bus work.
7. Return starter to normal operation.
End of Life and Equipment Disposal —
This
equipment has an average design life span of 25 years and is
constructed of primarily steel and copper. Content of control
panels includes but is not limited to common electrical compo-
nents such as fuses, starters, circuit breakers, wire, and printed
circuit boards.
Prior to retiring of equipment, it will be necessary to remove
all fluids such as water, refrigerant, and oil using the current in-
dustry guidelines for recovery and disposal.
Physical Data —
Tables 18A-25 and Fig. 58-70 provide
additional information on component weights, compressor fits
and clearances, physical and electrical data, and wiring sche-
matics for the operator’s convenience during troubleshooting.
CAUTION
If any red or white SCR gate leads are removed from the
firing card or an SCR, care must be taken to ensure the
leads are replaced EXACTLY as they were (white wires to
gates, and red wires to cathodes on both the firing card and
SCR), or damage to the starter and/or motor may result.
LOADER BAR
INDICATOR
WA
S
HER (
S
)
BOLT
S
Fig. 57 — SCR Installation
a19-
1884
Summary of Contents for AquaEdge 19XR series
Page 69: ...69 Fig 33 19XR Leak Test Procedures a19 1625 ...
Page 154: ...154 Fig 64 Benshaw Inc Wye Delta Unit Mounted Starter Wiring Schematic Low Voltage a19 1873 ...
Page 161: ...161 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v ...
Page 162: ...162 Fig 69 Typical Low Voltage Variable Frequency Drive VFD Wiring Schematic 575 v cont ...
Page 186: ...186 APPENDIX B LEAD LAG WIRING 19XR Lead Lag Schematic Series Cooler Flow a19 1655 ...
Page 187: ...187 APPENDIX B LEAD LAG WIRING cont 19XR Lead Lag Schematic Parallel Cooler Flow a19 1717 ...