Single Phase Motors - Final

Used to disconnect the start winding when the motor reaches 75 percent of its rated speed.

What is the purpose of the centrifugal switch?

Black Red Blue White - Neutral

What is the standard color code for a three phase 208 volt system?

Oil Filled Capacitor

What type of capacitor is connected in series with the run windings of a single phase split phase capacitor run motor?

AC electrolytic capacitor

What type of capacitor is connected in series with the start windings of a single phase capacitor start split phase motor?

120 degrees

The voltages of a three phase system are ________ out of phase with each other.

90 degrees

The voltages of a two phase system are ________ apart?

Series, Shunt, Compound

What are the three types of DC rotating machines?

The rotating magnetic field around a stator.

What is the principal of operation of all three phase motors?

Capacitor Bank - Used for power factor correction.

What is the purpose of 3 capacitors connected in parallel with the stator of a three phase induction motor?

Brown Orange Yellow Grey - Neutral

What is the standard color code for a three phase 480 bolt system?

The strength of the magnetic field of the stator. The strength of the magnetic field of the rotor. Phase angle difference between the start winding and the run winding.

What three factors determine the starting torque of a single phase split phase motor?

The number of stator poles per phase The frequency of the applied voltage.

What two factors determine the speed of a single phase split phase motor?

Squirrel Cage Rotor

What type of rotor does the single phase shaded pole motor have?

No

Do all single phase motors operate on the principle of a rotating magnetic field?

plus or minus 10 percent.

Motors are generally designed to operate within_________ of the nameplate value.

The amount the motor can be operated overload for a short period of time without damaging the motor.

When interpreting motor nameplate information, what does Service Factor indicate?

When the start winding current and the run winding current are 90 degrees out of phase with each other.

When is maximum starting torque developed in a single phase split phase motor?

75 percent

A centrifugal switch in a single phase split phase motor opens when the rotor reaches approximately ______ of full load speed.

If too little or too much capacitance is used, the starting current will be more or less than 90 degrees out of phase. The starting torque will be reduced.

If a capacitor is to be replaced in a capacitor start induction run motor, why is it very important to use the correct microfarad rating?

Device that converts electrical energy into mechanical energy.

Define Motor :

Device used to convert mechanical energy into electrical energy.

Define Generator :

Physically remove poles, turn and reinstall.

Although not very common, how can the direction of rotation of a single phase shaded pole motor be changed?

Yes

Are single phase shaded pole motors induction motors?

No, Higher starting torque but the running characteristics are identical.

Do capacitor start induction run motors have higher running torque than resistance start induction run motors of the same horsepower, voltage, size, etc?

No. They receive an induced voltage

Do squirrel cage rotors receive current from the line through brushes?

No, relatively high starting torque.

Does a single phase series ac motor have a comparatively low starting torque?

No, comparatively weak starting torque.

Does a single phase shaded pole AC motor have a comparatively high starting torque?

Determined by facing the back or the rear of the motor.

How is the direction of rotation of a single phase split phase motor determined?

Reverse connection of the start winding or the run winding, usually the start winding.

How is the direction of rotation of a single phase split phase motor reversed?

Changing armature leads with respect to the field leads.

How is the direction of rotation of a single phase universal motor changed?

By swapping any two stator leads.

How is the direction of rotation of a three phase motor reversed?

Large wire placed a the bottom of the rotor core, high inductive reactance.

How is the run winding of a resistance start induction run motor constructed?

Parallel

How is the start and run windings of a single phase split phase motor connected in relation to each other?

Starting Relay

How is the start winding of a hermetically sealed single phase split phase motor generally disconnected?

Centrifugal Switch

How is the start winding of a non hermetically sealed single phase split phase motor generally disconnected?

Small wire placed near the rotor, High Resistance.

How is the start winding of a resistance start induction run motor constructed?

746 watts

How many watts are equal to one horsepower?

90 degrees

In a capacitor start induction run motor, the capacitor causes the current in the start winding to lead the applied voltage, resulting in a ________ angle displacement between the start and run winding currents.

Series

In a duel voltage single phase split phase motor connected for HIGH VOLTAGE, the two sets of run windings will be connected in _______ as well as the two sets of start windings.

Parallel

In a duel voltage single phase split phase motor connected for LOW VOLTAGE, the two sets of run windings will be connected in _______ as well as the two sets of start windings.

Poor

In a resistance start induction run motor, a phase angle difference of 35-40 degrees is produced between the run winding current and the start winding current during the starting period. This results in a _______ torque.

Power tools and household appliances.

Single phase universal motors are used where light weight and high horsepower are needed, name some examples.

AC electrolytic capacitor

Some capacitor start capacitor run motors use a second capacitor during the starting period to improve torque. This capacitor is generally an _________ capacitor?

Fans

Some examples of single phase shaded pole motors are?

Resistance Start - Induction Run Capacitor Start - Induction Run Capacitor Start - Capacitor Run

What are the three main types of single phase split phase motors?

Wound Rotor Induction Squirrel Cage Induction Synchronous

What are the three types of three phase motors?

The fact that the AC motor contains a compensating winding on the stator hooked in series.

What is one of the main differences between a single phase series AC motor and a series DC motor?

Swap any two leads on the armature.

What is the most accepted method to reverse the direction of rotation of DC motors?

Universal Motor

What is the most common type of motor that can be operated with both AC and DC sources?

One phase split into two to create a rotating magnetic field.

What is the principal of operation of a single phase split phase motor?

Squirrel Cage Rotor

What type of rotor does the single phase split phase motor have?

It would be damaged by excessive current flow.

What would happen if the start winding of a resistance start induction run motor was not disconnected?

Different operating characteristics.

Why should one NEMA design induction motor not be replaced with any other NEMA design?