help!!! split single phase motor

[lloyd67]

hi guys
how can i reverse the direction of a split single phase motor
many thanks lloyd

 

[ScottyUK]

The quickest method, depending on the design, is to remove the ends of the motor, turn the rotor 180 degrees end-for-end, and reassemble. It will then run backwards.

Failing this, you will have reverse the connections one or other of the windings. Normally this involves digging out the junction of the start and run windings on the stator and bringing them out separately. You can then wire as required for either direction.



-----------------------------------

Start each new day with a smile.

Get it over with.

 

[jbartos]

Suggestion: If the motor cooling fan permits (some motors are designed to run in one direction only), switch the motor starting leads connections to the stator main winding.

 

[jbartos]

Suggestion: Visit

http://www.orientalmotor.com/products/pdfs/A_OM/AcInd2Pole.pdf

and look for the Connection Diagram at the end.

 

[aolalde]

If you could access the starting winding leads, reverse them. Leave the main winding as the originally found.
A split-phase phase motor is a single phase induction motor with an auxiliary winding, providing some magnetic displacement as compared to the main winding. It uses the auxiliary winding impedance alone to achieve the magnetic displacement. After the motor starts the auxiliary circuit is opened.
Regularly you will be able to identify the auxiliary from the main winding for the resistance values. Auxiliary windings will have the high value.

 

[nbucska]

What you call "single phase" motor is really a two phase
motor. The main phase is the incomming AC, the auxiliary
phase is generated by a phase shifting device which
may be a capacitor or resistor connected to a second
coil or a short circuit around one ( right or left) ends
-- e.g. one third or half -- of the main poles.

If C or R then you can reverse the polarity of either
the main or the aux. coil. If shorted, you can remove
the shorts, cut a grove on the other side of the poles
and add two coils to each pole. These coils should have
many turns and shorting one or the other you can reverse
the motor.

If not clear, send FAX# for sketch.


<nbucska@pcperipherals.com>

 

[ScottyUK]

Further to nbucska's comments,

The resistor referred to is often incorporated in the starting winding by winding it with thin wire to arranged to give low inductance and high resistance. This gives a phase shift relative to the main winding which has lower resistance and higher inductance.



-----------------------------------

Start each new day with a smile.

Get it over with.

 

[nbucska]

thin or even wire of an alloy with higher sp.resistance --
i.e. not Cu. It is usual to disconnect the aux. phase
after the motor is at speed. The phase shift is less than
90 deg.



<nbucska@pcperipherals.com>

 

[aolalde]

I disagree with the statement: “What you call "single phase" motor is really a two phase
motor.”

Unless other wise specified, the starting or auxiliary winding is used only during the starting condition. SPLIT-PHASE MOTOR used without qualification, describes a motor to be used without impedance other than that offered for the motor windings themselves, other types (Resistance-start, Capacitor-start, Permanent-split capacitor or two values Capacitor) being separately defined. When a short-circuited auxiliary winding is used, the name is SHADED-POLE MOTOR. See NEMA MG1 Standard.

In regard to the phases, this can not be a two phase motor; Per IEEE Std-100:

“TWO-PHASE CIRCUIT. A polyphase circuit of three, four, or five distinct conductors intended to be so energized that in the steady state the alternating voltages between two selected pair of terminals of entry, other than the neutral terminal when one exists, have the same periods are EQUAL IN AMPLITUDE, and HAVE A PHASE DIFFERENCE OF 90 DEGREES. When the circuit consists of five conductors but not otherwise, one of them is a neutral conductor. Note: A two phase circuit as defined here does not conform to the general pattern of polyphase circuits. Actually a two-phase, four wire or five wire circuit could more properly be called a four phase circuit, but the term two-phase is in common usage. A two-phase three wire circuit is essentially a special case, as it does not conform to the general pattern of other polyphase circuits.

TWO-PHASE FIVE-WIRE SYSTEM. A system of alternating-current supply comprising five conductors, four of which are connected as in a four wire two-phase system, the fifth being connected to the neutral points of each phase. Note: The neutral is usually grounded. Although this type of system is usually known as the two-phase five wire system it is strictly a four-phase five wire system.

TWO-PHASE FOUR- WIRE SYSTEM. A system of alternating-current supply comprising two pairs of conductors between one pair of which is maintained an alternating difference of potential displaced in phase by one quarter of a period from an alternating difference of potential of the same frequency maintained between the other pair.

TWO-PHASE THREE- WIRE SYSTEM. A system of alternating-current supply comprising three conductors between one of which (known as the common return) and each of the other two are maintained alternating differences of potential displaced in phase by one quarter of a period with relation to each other.”

 

[lloyd67]

thanks very much for you reply's particulary to aoladle for his in depth reply.
i have now sorted out the problem, it was more for the knowledge of how to than the need, as jbartos said the cooling fan will not work in reverse. & yes its a motor with a seperate starting winding the second winding is disengaged by a centrafugal switch.
many regards lloyd