Question 1

The sensing network continuously monitors the motor line currents.

Accepted Answer

The sentence clearly states that the sensing network continuously monitors the motor line currents. The statement is true as the sensing network is designed to continuously monitor the motor line currents.

Question 2

A built-in delay of five cycles prevents nuisance dropouts caused by fluctuating line voltages.

Accepted Answer

The statement mentions a built-in delay of five cycles that prevents nuisance dropouts caused by fluctuating line voltages, indicating that the statement is true. The statement mentions that there is a built-in delay of five cycles which prevents nuisance dropouts caused by fluctuating line voltages. Therefore, the statement is true.

Question 3

A solid-state phase monitoring relay provides protection in the event of a(n) .&#10;A)power failure&#10;B)power brownout&#10;C)phase reversal&#10;D)abrupt startup

Accepted Answer

A solid-state phase monitoring relay is designed to detect phase reversal in a three-phase power system. When it detects phase reversal, it can quickly disconnect the equipment from the power source to prevent damage. It does not provide protection against power failure, power brownout, or abrupt startup. A solid-state phase monitoring relay is designed to monitor the phase sequence and voltage levels of a three-phase AC power supply. It can detect phase reversal, which could cause damage to motors and other equipment that rely on consistent phase sequence. It does not provide protection for power failures or brownouts, and abrupt startup is not a relevant event in this context.

Question 4

A solid-state phase monitoring relay provides protection in the event of a(n) .&#10;A)power failure&#10;B)power brownout&#10;C)abrupt startup&#10;D)voltage unbalance

Accepted Answer

A solid-state phase monitoring relay provides protection against voltage unbalance, which occurs when the voltage supplied to three-phase equipment varies for any reason, such as a blown fuse or a faulty connection. This can cause the equipment to operate inefficiently, overheat, or fail prematurely. A phase monitoring relay detects voltage imbalances and shuts down the equipment to prevent damage. It does not provide protection in the event of power failure, brownout, or abrupt startup. A solid-state phase monitoring relay monitors the voltage levels on all three phases of a power system and provides protection in the event of voltage unbalance, which can cause damage to motors and other equipment. Power failure, power brownouts, and abrupt startup are not directly related to voltage unbalance and therefore not the best choice for this question.

Question 5

One type of relay consists of a static, current-sensitive network connected the line and a switching relay connected in the coil circuit of the starter.&#10;A)in series with&#10;B)below&#10;C)next to&#10;D)in parallel with

Accepted Answer

A relay in series with the coil circuit of the starter is used to control the current flow and protect the starter from damage due to overloading. A relay that is connected in the coil circuit of the starter should be in series with the circuit, not in parallel or below it. The current-sensitive network allows the relay to detect when a fault occurs in the line, and the switching relay in series with the starter coil circuit is used to disconnect the starter from the line in case of a fault.

Question 6

Motor protector modules feature phase forward.

Accepted Answer

Motor protector modules typically feature phase failure protection, not phase forward, to protect motors from issues like phase loss, imbalance, or reversal.

Question 7

are used for the input to the motor protector module.&#10;A)Spike suppressors&#10;B)Current transformers&#10;C)Voltage regulators&#10;D)UPSs

Accepted Answer

Current transformers are used to measure the current going to the motor and provide an input signal to the motor protector module for overcurrent protection. Spike suppressors protect against sudden voltage spikes, voltage regulators regulate the voltage, and UPSs provide backup power in case of a power outage, but none of them are specifically used for input to the motor protector module. Current transformers are typically used for the input to the motor protector module as they allow for measurement of the motor currents, which can be used to detect overcurrent conditions and protect the motor. Spike suppressors are used to protect against voltage spikes, voltage regulators are used to maintain a stable voltage, and UPSs are used to provide backup power in case of a power outage, but none of these are directly related to motor protection.

Question 8

Motor protector modules feature instantaneous fault protection.

Accepted Answer

Motor protector modules are designed to provide instantaneous fault protection to the motor against various faults like overload, underload, phase failure, and others. Motor protector modules are designed to provide instantaneous fault protection to the motor they are connected to.

Question 9

If two phases of the supply to a three-phase induction motor are interchanged, the motor will stop.

Accepted Answer

Interchanging two phases of the supply to a three-phase induction motor will not stop the motor; instead, it will cause the motor to run in the opposite direction.

Deck 14: Phase Failure Relays