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HVAC
HVAC Excellence Professional Level Technician
Electrical Troubleshooting - Capacitors, Contactors & Motor Testing
Knowledge Check
Electrical Troubleshooting - Capacitors, Contactors & Motor Testing
Knowledge Check
Knowledge Check
1 / 15
A contactor is tested by measuring voltage drop across the closed contacts under load. A reading of 4.5V across the contacts indicates:
A
Failed contacts requiring immediate replacement - acceptable voltage drop is 0 to 1V, and 1 to 3V is marginal; anything above 3V indicates severely pitted contacts causing resistance heating that will destroy the contactor
B
Acceptable operation since the full line voltage is present at the load terminals
C
Normal operation - voltage drop up to 5V is acceptable on all contactors
D
Marginal operation - plan for replacement at the next maintenance visit
Check Answer
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