Motors Level 2 study guide

Reversing

(Blank) a shaded-pole motor is very different from reversing the usual single-phase motor. In many cases, the rotor must be removed from the housing and turned around so that the shaft exits the opposite side of the housing

Shaded-pole motors

(Blank) are commonly 1/20th HP or less and have low starting torque

115%

430.110(C)(2) Exception: A listed nonfused motor-circuit switch having a horsepower rating equal to or greater than the equivalent horsepower of the combined loads, determined in accordance with 430.110(C)(1), shall be permitted to have an ampere rating less than (blank) of the sum of all currents at the full load condition

Failure to start

430.31 General: Part III specifies overload devices intended to protect motors, motor control apparatus, and motor branch-circuit conductors against excessive heating due to motor overloads and (blank)

Higher

430.52(C)(1)Exception NO. 1: where the values for branch circuit short-circuit and ground fault protective devices determined by Table 430.52 do not correspond to the standard sizes or ratings of fuses, nonadjustable circuit breakers, thermal protective devices, or possible settings of adjustable circuit breakers, a higher size, rating, or possible setting that does not exceed the next (blank) standard ampere rating shall be permitted

thermal-magnetic

A (blank) circuit breaker uses a bi-metal strip connected in series with the load to open a circuit.

Overload

A (blank) in a motor is caused by a load that exceeds the full-load rating of the motor

Capacitor

A (blank) is a device that stores an electrical charge

split phase motor

A (blank) is a single phase AC motor that includes a run winding and a resistive start winding used in applications where starting is easy, such as fans, business machines, machine tools, and centrifugal pumps

Three-pole Rheostat

A (blank) is a switch with tapped resistors used to switch a set of resistors in and out of a wound-rotor circuit. It can be manually controlled or motor driven

Permanent split capacitor motor

A capacitor run motor is also known as a (blank)

180°/120°

A single phase stator is nearly identical to a three phase stator, except that the windings in the single-phase stator are placed (blank) apart in the slots. The windings in the three-phase stator are placed (blank) apart

6000A

Cartridge fuses are available with amperage ratings from 0 amperes to (BLANK)

Compound

DC (blank) motors are used mostly for special applications that require constant speed under load and high starting torque

Drum switch

If a capacitor-start motor is to be reversed often, then a (blank) or foot switch can be used to reverse the current through the start with respect to the run windings

Shunt field

In a compound wound generator, the (blank) is normally stronger than the series field

90 mechanical degrees

In a two-pole single phase motor, the start winding is placed (blank) from the run windings in a 2 pole motor

Start/Run

In many cases, a single-phase motor is constructed with both (blank) and (blank) winding in the stator

overcurrent protection

The NEC requires (blank) of motor installations

Black and Red/ T5 and T8

To reverse the direction of most single phase motors, all that is necessary is to switch the two start leads in the circuit. These leads will be colored (Blank) or marked (blank)

40%

When the split phase motor is turned OFF (power removed), the centrifugal switch recloses at approximately (BLANK) of full-load speed

Centrifugal switch

When the split phase motor reaches approximately 75% of full speed, the (blank) opens, disconnecting the start winding from the circuit

Resistance

Wound rotor starters usually have one or more timers used to automatically remove (blank) from the rotor circuit