Toggle switch to reverse rotation

[wilton]

I purchased a new Marathon ½ hp 115/230 V motor to replace bad attic fan motor. It provides for reversing the rotation of the shaft by switching the black and red wires in the motor as shown here. The motor runs and reverses when directly connected.

I want to put an on-off-on toggle switch in the circuit to reverse the rotation for seasonal and other changes. This diagram shows a recommendation that I have been following. I have A-F connected and B-E connected in a crisscrossed configuration to achieve the connections shown. The wire from C (red) goes to the internal connection that was removed from the red wire that was swapped to reverse the rotation. Likewise for the wire from D(Blk) to the black wire that was swapped to reverse the rotation.


I connected the neutral (white) line from the power supply to the Terminal 1 in the motor. The ground wire is connected to the green terminal in the motor.

My questions are:

• Should this work and
• Where should the hot (black) wire from the power supply be connected?

I have tried several connections of the hot (black) wire but the motor has not run from any of them. Some cause a hum. Some a spark at the plug in.

The motor does run when direct connected and it swaps rotation when manually changed.

Thanks for any suggestions and help.
Wilton

 

[GrifterGuru]

The below diagram shews a wide-spread method of using a DPDT to reverse polarity. I am categorically NOT saying this is how you should do this, it is merely there as an example.

It may, however, be better / easier to use a rotary on/off/on switch such as is used on 7x lathes and other variable speed machines with F/O/R rotary switches.

 

[Huub Buis]

I use this DPDT (ON-OFF-ON) switch to reverse the DC motor of my manual mill and It works great. That DPDT switch is pretty small so it fits in the current controll box besides the pot meter. The rotary ON-OFF-ON switch, like the one on my lathe, is to big to fit the manual mill.

 

[wilton]

The below diagram shews a wide-spread method of using a DPDT to reverse polarity. I am categorically NOT saying this is how you should do this, it is merely there as an example.

It may, however, be better / easier to use a rotary on/off/on switch such as is used on 7x lathes and other variable speed machines with F/O/R rotary switches.
View attachment 499350

Thanks you. I think this is the wiring configuration I have on the toggle switch also. My question though is where does the 120 V power line connect. Does it go direct to the normal power terminal in the motor. In my connections the Input lines shown on your DPDT connect to Terminals in the motor where the lines that go to your Output post on the toggle were disconnected. I wonder if those should be reversed.
Thanks

 

[wilton]

The below diagram shews a wide-spread method of using a DPDT to reverse polarity. I am categorically NOT saying this is how you should do this, it is merely there as an example.

It may, however, be better / easier to use a rotary on/off/on switch such as is used on 7x lathes and other variable speed machines with F/O/R rotary switches.
View attachment 499350

My mistake. see above reply.

 

[GrifterGuru]

Power goes INTO the switch at one end (Input 1 & Input 2) and crosses over before going to the opposite end terminals. Power OUT comes from the middle 2 terminals.

Basically, feed goes into the switch, wires from switch centre posts (Output 1 & Output2) go to motor.

The switch lever (the bit you toggle) flips a pair of bars inside the switch like a see-saw, disconnecting one pair of terminals (power in end) and engaging the other (polarity reversed) end. Output polarity through the centre terminals is determined by the switch being flipped from one, to the other, position.

 

[gard]

One option is to use a 4 way light switch to change motor direction, it has 4 connections and internal jumpers so easy to wire. Then use a seperate switch to turn the motor off and on.

The vertical line on the right of your diagram implies the motor wires are shorted so that is not right. I think the grifterguru diagram is correct, the 4 way light switch has these jumpers internal but you can add them to a toggle switch if space is more limited. This does not turn the motor on, just changes direction.

If you want 1 switch to do both things, I am not sure about that.

 

[GrifterGuru]

If you want 1 switch to do both things, I am not sure about that.

Using the pole-reversing switch assumes that another, inline, SPST on/off switch (in the positive/feed power wire) comes before the pole reverse switch to ensure the motor is not powered when it is switched from forwards to reverse and causes a momentary electrical stall and/or possible arc that can damage the windings.

At least, that is how it was explained to me by several electricians. It may just be a way to say "dont reverse polarity of a running motor, wait until it stops before switching direction" which should be common sense.

You dont shift into reverse at speed in a car (not that you could even if you tried!), so don't do it with electrical motors.

Did actually get the point when accidentally I flipped the switch from forwards to reverse on my mains power hammer drill once due to the way I was holding it. Not something I have ever repeated since!! The momentary arc from the comm and brushes as well as the jolt from the reversal whilst the armature was still spinning was warning enough never to do that again.

 

[RJSakowski]

Using the pole-reversing switch assumes that another, inline, SPST on/off switch (in the positive/feed power wire) comes before the pole reverse switch to ensure the motor is not powered when it is switched from forwards to reverse and causes a momentary electrical stall and/or possible arc that can damage the windings.

At least, that is how it was explained to me by several electricians. It may just be a way to say "dont reverse polarity of a running motor, wait until it stops before switching direction" which should be common sense.

You dont shift into reverse at speed in a car (not that you could even if you tried!), so don't do it with electrical motors.

Did actually get the point when accidentally I flipped the switch from forwards to reverse on my mains power hammer drill once due to the way I was holding it. Not something I have ever repeated since!! The momentary arc from the comm and brushes as well as the jolt from the reversal whilst the armature was still spinning was warning enough never to do that again.

A capacitor start motor won't do anything if the motor is reversed at speed. The circuit is open due to the centrifugal switch and won't become a closed circuit until the motor slows enough to close that switch. If the motor is reversed and the power is cut and reapplied before the motor slows enough to close the centrifugal switch, the motor will continue to run in the same direction. If the motor has slowed enough to close the centrifugal switch, the motor will reverse albeit with a higher current due to the momentum of the still spinning motor.

 

[GrifterGuru]

A capacitor start motor won't do anything if the motor is reversed at speed. The circuit is open due to the centrifugal switch and won't become a closed circuit until the motor slows enough to close that switch. If the motor is reversed and the power is cut and reapplied before the motor slows enough to close the centrifugal switch, the motor will continue to run in the same direction. If the motor has slowed enough to close the centrifugal switch, the motor will reverse albeit with a higher current due to the momentum of the still spinning motor.

As I noted above, I was told that by electricians, so rightly or wrongly, that is what I was led to beleive.

Your post clarified the situation and made things a little clearer not just to me, but to others as well.