IOMM ACZ/AGZ-1
97
3.
Remove power from the controller by opening CB1. Try to improve the connections in the
Aux/Out plug insulation displacement terminals by pressing down on the wires with a small
screwdriver.
4.
Check all other wiring and connectors for bent pins or mis-wires.
If the chatter does not stop, the electromechanical relay or contactor is probably defective.
Troubleshooting Solid-State Relays
As shown on the unit wiring diagrams, the Solid-State relays on the Output Boards all have normally
open “contacts.” Actually, these contacts do not exist as they do in an electromechanical relay.
Instead of using contacts to switch the load, the Solid-State relay changes its resistance from low
(closed), when it is energized, to high (open), when it is de-energized. (This high resistance is
approximately 100K ohms.) Because the output circuit through the Solid-State relay remains
continuous regardless of whether the relay is energized, troubleshooting a Solid-State relay with a
voltmeter can be tricky.
In a typical circuit, a power source is connected across a single relay output and a load. In this circuit,
a Solid-State relay will behave like an electromechanical relay. If the relay is energized, the relay output
will be hot. If the relay is de-energized, voltage cannot be measured at the relay output.
The circuit shown in Figure 35 is similar to a typical circuit; the difference is that there is an open set
of contacts, or a disconnection between the relay output and the load. In this circuit, a Solid-State
relay will not behave like an electromechanical relay. if the Solid-State relay is energized, the relay
output will be hot (as expected). However, if the Solid-State relay is de-energized, the relay output will
still appear to be hot. This is because the relay output and the voltmeter form a continuous circuit in
which the relay’s resistance, though high, is insignificant compared to the voltmeter’s resistance.
This means that nearly all the voltage is dropped across the voltmeter. Therefore, the voltmeter
indicates that voltage is present. If a low wattage light bulb of the appropriate voltage is used instead
of a voltmeter, the bulb’s low resistance will load the circuit enough to eliminate the false voltage
indication. In this situation, an incandescent test lamp is a better tool than a voltmeter.
Figure 35, Testing a Typical Relay Circuit
Figure 36, Testing a Relay Circuit with a Disconnection
M10
0V
115 VAC
Output Board
DO 13
28
27
Neutral
M10
115V
115 VAC
Output Board
DO 13
28
27
Neutral
Содержание ACZ 045A
Страница 6: ...6 IOMM ACZ AGZ 1 Figure 3 Clearance Requirements...
Страница 27: ...IOMM ACZ AGZ 1 27 Figure 12 AGZ AM Single point Connection with FanTrol...
Страница 28: ...28 IOMM ACZ AGZ 1 Figure 13 AGZ AM Single point Connection with SpeedTrol...
Страница 29: ...IOMM ACZ AGZ 1 29 Figure 14 AGZ AM Unit Control Schematic UNT...
Страница 30: ...30 IOMM ACZ AGZ 1 Figure 15 AGZ AM Staging Schematic UNT...
Страница 31: ...IOMM ACZ AGZ 1 31 Figure 16 AGZ AM MicroTech Controller Schematic...
Страница 32: ...32 IOMM ACZ AGZ 1 Figure 17 AGZ AM Unit Control Schematic MicroTech...
Страница 33: ...IOMM ACZ AGZ 1 33 Figure 18 AGZ AM Staging Schematic MicroTech...
Страница 34: ...34 IOMM ACZ AGZ 1 Figure 19 ACZ Field Connection Diagram No Capacity Control...
Страница 35: ...IOMM ACZ AGZ 1 35 Figure 20 ACZ Field Wiring Diagram Capacity Control Staging...
Страница 104: ...Post Office Box 2510 Staunton Virginia 24402 2510 USA 800 432 1342 www mcquay com...
