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20 Cards in this Set
- Front
- Back
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What is the primary reason AC relays hum or chatter? |
AC cycle reversal |
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Which of the following best describes the contact rating of a magnetic switch? |
The maximum voltage and current that can be safely interrupted |
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How can you reduce contact arcing on plug-in relay contacts? |
Wire two contacts of the same relay in series |
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Which of the following is a relay commonly used for circuits on solid state equipment? |
Reed relay |
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How are latching relays reset? |
Electrically |
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How are magnetic set/reset relays that use a center tapped coil reset? |
By energizing the reset winding |
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Testing with a multimeter, full line voltage is read directly across the door close relay coil. The coil however will not pull in. Which of the following is most likely the problem? |
Open coil |
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When working on unfamiliar wiring diagrams, what are good clues to finding contact numbers? |
Tracing self-holding contacts |
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What would the data, 120 NC 8, printed on the side of a bi-metallic timer represent? |
An 8 second timer with normally closed contacts and 120 volts |
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Which of the following steps would be most appropriate when arriving on a trouble call of a failed relay controller? |
Leave the circuit in the failed state for troubleshooting |
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What are normally closed (NC) contacts commonly referred to as? |
Breaking contacts |
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If a relay with the contact arrangement shown in Figure 1 was energized, which contacts would break?
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2 and 8 |
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What type of circuit does Figure 2 represent? |
On-delay timing circuit |
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Refer to Figure 2. What would happen in the circuit if resistor R1 were open? |
Capacitor C1 would not charge properly |
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Which of the following is characteristic of a capacitor? |
When charged, the negative connected plate has an accumulation of electrons |
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When fully charged, what does capacitor voltage equal? |
100 percent of the source voltage |
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When a diode or resistor is connected in parallel across a coil, how is a short delay time achieved? |
The collapsing field |
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Refer to Figure 3. When the switch is closed, then opened, what will happen to Relay 1 and Relay 2? |
Relay 1 off-delay, Relay 2 drops immediately |
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What is a walking beam? |
A mechanical beam that prevents two opposite electrical functions from occurring simultaneously |
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Which is the most common reason for capacitor failure? |
Dielectric shorting |
