E2 Motors and Motor Starting (Modified)

Name: E2 Motors and Motor Starting (Modified)
Uploaded: 2017-06-27T12:47:30+00:00
Duration: PTM30S46
Channel: Harley Birdsey
Description: E2 Motors and Motor Starting (Modified)

E2 Motors and Motor Starting (Modified)
#1 Fan Motors

© 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2
Basic Electric Motor Stator Stationary electromagnet Rotor Rotating magnet Movement of the rotor Rotates by repulsion and attraction of stator © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

_ + Two-pole stator motor N S S N N S Stator Rotor (Stationary)
(Rotates) N S S N N S Polarity reverses (N to S) on stator Stator repels & attracts rotor into motion _ When stator is energized the rotor will make a half turn with each half of current cycle + © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

_ + Second half of cycle N S S N N S
Stator continues motion by repelling and attracting Polarity reverses (N to S) on stator _ + The alternating current now changes direction © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Motor Tries to Start N S Power applied to stators S
Equal and opposite attraction Rotor S N Opposite attraction Rotor will NOT move Equal and opposite attraction S Stator © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

A Phase Shift is Needed Stator N A phase shift causes rotation Rotor S N A magnetic field is formed at a slightly different angle This phase shift can be caused by: A shaded pole A start winding A capacitor 3 separate phases S Stator © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Examples of Shaded-Pole Motors
© 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Starting a Shaded-Pole Motor
Each pole has a copper band attached The shaded-pole provides the phase shift needed to start rotation Usually impedance protected A stalled blade will not cause burned windings © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Rotation toward the Shaded Pole

Shaded-Pole Motor Wiring
COMMON LINE BLACK LINE GREEN GROUND © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Changing Motor Rotation
Shaded-pole motors can be reversed: First, turn stator around Second, turn blade around © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Interesting Motor Fact
Motor efficiency: A 100 watt 50% efficient motor will put out 50 watts of work, and 50 watts of heat. © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Shaded-pole C-frame Motor

Multi-speed Shaded-Pole Motors
Speed depends on winding resistance Low speed: most resistance High speed: least resistance Motor speed is based on where power is connected into the winding High Speed Medium Speed Low Speed Common © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Shaded-Pole 3-Speed Motor Wiring
COMMON LINE Common Wire is White (115v) or Black (230v) BLACK-HIGH BLACK LINE LINE BLUE-MED RED-LOW GREEN GROUND © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Split Phase Motors Have two separate windings, a run and a start The start winding provides the phase shift for starting More efficient and have more torque than shaded pole motors © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

A Split Phase Motor is a Two-pole stator motor …
with Start Windings added Start Run TO RUN WINDINGS R C TO START WINDINGS S © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Start & Run Winding Resistances
START WINDING COM V/  V AC DC S Ω Ω Ω R © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Windings of a split phase motor
Run Windings Start Windings © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Split Phase Motor S This motor needs power to the start winding to start C R START WINDING RUN WINDING This motor needs power to the run winding to run A split phase motor is the basic design for motors used in all HVACR applications. The run winding uses heavy wire, while the finer wire of the start winding provides the resistance and phase shift necessary to start the motor. Once the motor is started we need to take the start winding out of the circuit. We can accomplish this with either a current relay or a potential relay. This motor needs a start winding for a phase shift LINE © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Fan Motor with Centrifugal Switch
A mechanical switch is used to de-energize the start winding The switch is attached to the motor shaft After the motor starts, centrifugal force opens the switch The start winding circuit remains open as long as the motor is running © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Split Phase Motor with Centrifugal Switch
Centrifugal switch opens start winding C R S START WINDING RUN WINDING A split phase motor is the basic design for motors used in all HVACR applications. The run winding uses heavy wire, while the finer wire of the start winding provides the resistance and phase shift necessary to start the motor. Once the motor is started we need to take the start winding out of the circuit. We can accomplish this with a centrifugal switch (above) on an open motor, like a fan motor. However enclosed motors, such as compressor motors, use switches like current relays and potential relays. If the switches were located inside the compressor with the motor windings a spark from the contacts could cause the oil and refrigerant vapors to explode. LINE © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Fan Motor with Centrifugal Switch
The next slide is a picture of a fan motor with the motor cover removed The centrifugal switch is attached to the motor shaft The switch contacts are attached to the end bell (motor cover) © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Motor with Centrifugal Switch
Weights shift, disk moves back Motor Speed Increases Start winding energized Before starting, disk pushes bar, closing contacts Contacts Open To Start Winding Centrifugal Switch Disk From Run Winding © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Permanent Split Capacitor Motors
A run capacitor is “permanently” wired into the start winding circuit The capacitor provides partial voltage to the start winding, during start and run © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

PSC Motor with run capacitor
Low Starting Torque Low to Medium Cost Medium Efficiency © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Split Phase Motor + Run Cap = PSC Motor
RUN WINDING START WINDING S R Run Capacitor © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

PSC Motor Wiring Diagram
COMMON LINE BLACK LINE BROWN W/ WHITE BROWN GREEN GROUND CAPACITOR © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Calculating ‘Synchronous’ Motor Speeds
One cycle has two current flow reversals 60 cycles has 120 flow reversals Speed = (60 Hz x 120 reversals) ÷ Poles Example: 7200 ÷ 2 Motor poles = 3600 RPM © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Two Pole Motor Windings
2 Run Windings 2 Start Windings Two Pole Motor Windings Here is a 2-pole stator that runs at 3,500 rpm. The large red windings are the run windings. The small green windings are the start windings. They are smaller for two reasons, one is because the smaller wire resists the flow of electrons which changes the phasing slightly. The second reason is that the small windings are not in the circuit for over 3 seconds. The start winding has more turns and smaller wire than the run winding. Courtesy of Copeland 7200  2 = 3600 RPM © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

4 Run Windings 1 2 1 4 Start Windings Four Pole Motor 4 2 7200  4 = 1800 RPM Here is a 4-pole stator with the end turns painted so that the poles of the main winding and the auxiliary winding are easier to see. 3 4 3 Courtesy of Copeland © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Actual ‘Rotor’ Motor Speed
Slippage is the loss of speed from motor load The ‘rotor’ speed is less than the ‘synchronous’ speed. Common motor speeds: Synchronous: ROTOR: 2 Pole motor: 4 Pole motor: 6 Pole motor: 8 Pole motor: © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Multi-Speed PSC Motors
Actually they are “Multi-horsepower” The windings are tapped so the motor is weaker, running slower under load Example of a 3-speed 1/3 HP motor: High speed is 1/3 HP Medium speed is 1/4 HP Low speed is 1/6 HP © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Single-Speed PSC Motor
RUN WINDING START WINDING S R Run Capacitor © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Single-Speed PSC Motor
RUN WINDING START WINDING R C S Run Capacitor © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

3-Speed PSC Motor Wiring Diagram
COMMON LINE BLACK-HIGH BLACK LINE LINE BLUE-MED RED-LOW BROWN W/ WHITE BROWN GREEN GROUND © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Multi-speed motors must be under a load to change speeds Example: A multi-speed blower removed from the blower compartment will run at high speed, no matter which speed tap is used © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

PSC 3-speed Motor Leads for changing motor rotation Run
Capacitor Leads Common Wire Low Speed (red) Medium Speed (blue) High Speed (black) © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Three Phase Motor Starting
No start windings or capacitors needed High torque because the windings are 120° out of phase © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

3Ø Motor – Wye Connections
L1 208 V 208 V T1 T3 T2 L2 208 V L3 © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

3Ø Motor – Delta Connections
240 V 240 V T3 T2 L2 240 V L3 © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Describing Common Motors
Motor descriptions include the following information: Type Enclosure Mounting © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Common Motor Types Shaded Pole Split Phase Permanant Split Capacitor
Three Phase © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Open Enclosure Types Totally Open Open Dripproof
Note: Prevents direct entry of moisture Clean and Mostly Dry Locations Clean and Dry Locations © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Enclosed Type Motors Totally Enclosed Air Over
Totally Enclosed Fan Cooled Cooling from system air passing over the motor body Cooling from fan forced air passing over the motor body Totally Enclosed are good for wet and dirty conditions © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Rigid Mount Motor housing is welded to the base

Belly Band Mounting Motor slides into ring. Then band is tightened

Stud Mounts Studs are bolted to fan guard or housing.

Motor Nameplate explained
MODEL 1/2 HP 1 PH 1075/3SPD RPM 60 HZ 115 VOLT 9.00 AMP USE 5.00 MFD 370 V. CAPACITOR Motor Nameplate explained © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Motor Nameplate wiring diagram
LINE BROWN YELLOW PURPLE ORANGE BLUE N.P.24X327501 RED BROWN WHITE LO MED HI CAPACITOR BLACK MOTOR SHIPPED AS SHOWN FOR CCW ROTATION FOR CW CHANGE YELLOW & ROTATION INTER ORANGE LEADS Motor Nameplate wiring diagram © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

Interesting Motor Facts
An overloaded motor (too small for the job): Lower speed, amperage above 10% of RLA, and overheating An under-loaded motor (too big for the job): Little change in speed, amperage 25% below RLA, and overheating © 2005 Refrigeration Training Services - E2#1 Fan Motors v1.2

E2 Motors and Motor Starting (Modified)

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