Reversing motor control

[RF Lighting]

Hi, does anyone have a link to a wiring diagram for a 3 phase reversing motor controller?

It is the sort used for up, down, stop on roller shutter doors etc, where two of the phases are swapped over to make the door close.

Thanks

 

[Pensdown]

It's often done on 2 mechanically interlocked contactors. The up button does one and the down button does the other. The phases are normally reversed on the switched side

 

[Lectrician]

Yup, mechanicaly or electricaly interlocked contactors (3 pole).

Common the outputs of the contactors together to feed the motor.

On the input side of the contactor, Take the brown phase to L1 of both contactors. Take the black phase to L2 of the first contactor, and L3 of the second. Take the grey phase to L3 of the first contactor, and L2 of the second.

Use the push buttons to operate the contactors - one up and one down. You will no doubt also have 2 limit switches aswell - open limit and close limit, both usually contained inside worm wheel drive. These will interupt the core from the push button to the contactor. The RED stop button will interupt the common feed to the up/down buttons. You may also have a lock strike which is in series with the red stop button, and breaks the cct when the lock is thrown accross.

Roller doors do not usually have latching contactors, so you need to hold the button in to operate the door. Reasons being that id ever the limit switches get pushed out of alignment due to door closing on something etc, the door isn't going to keep on trying to move, as you are there witnessing the problem. Also for safety due to people moving in/out etc.

There is also a possibilty of a thermal link in the motor (they don't use overloads on the contactors). The thermal link stays closed circuit when all is good, open circuiting when the temp rises. This goes in series with the red stop buttons again.

Usually, the door controls is 24v AC, so the contactor coil needs to be 24v AC.

There are many makes of door, but the commonest seems to Henderson. They usually come with a control panel to fit anyway, either with buttons on the front, or ready for you to add remote buttons.

 

[Spark123]

Image is for a standard forward reverse starter, take note of what Lectrician says re the limit switches may need to be ELV & control non-latching etc.

 

[simon_d]

RS do a contactor thats mechanically interlocked and already has the wire 'cross' ready for reverse. you just need to add a supply to pull the contactor in

 

[Pensdown]

Sparks123, I'm impressed! Sangamo time switch yesterday and now a wiring diagram from the 60's. Does your house back onto Neweys?

 

[Spark123]

I wasn't born till 1977 - my mate was having a clear out at work and out popped a crompton electric motor red book (which got claimed pretty fast )
The first time I came across Sangamo time switches was when I was an apprentice (back then in mid 90s ), we removed one from a set of private street lights as every time there was a power cut the timer stopped. Replaced it with a digital one.

 

[RF Lighting]

Cheers, my head hurts a bit but I managed to make a controller with two relays and two 3 pole contactors.

Turns out it was actually a single phase capacitor start motor, but same theory.

 

[Pensdown]

Sorry 123, I wasn't implying you were vintage, I was just impressed by some of your electrical memorabilia.

And although I'm not old, I was a second year apprentice when you popped out

 

[Spark123]

Just wait till the old man can't find his red book, there'll be hell to pay....