Colchester Chipmaster no-volt unit

[Daniel RobinsonParticipant @danielrobinson12697]

I have a Colchester Chipmaster which had been converted to
single phase with a couple of Capacitors. I have decided to bring it back to
three phases and have been stumped by the additional terminals on the no-volts
unit.>>

The unit is a Crabtree J.A.C. C.B.3 CAT 16021 …. I have taken other numbers from
it but nothing works in Google or at Crabtree. >>

What are the terminals BESIDE L1, L2 and L3 (image
IMG_0747) and how should they be connected?>>

> >>>

There are also the equivalent terminals beside
A1, B1 and C1 (image IMG_0745). Is this for an alternative wiring layout?

 

What are terminals 1,2,3 and 4 (image IMG_0740) located to
one side of the main no volt unit and how do these relate to L1, L2 and L3?>>

 

 

 

 

I apologise for all the questions but I am at a loss. Any
help would be appreciated.>>

 

 

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> >>>

> >

[Daniel RobinsonParticipant @danielrobinson12697]

pint out for the no-volt unit

[Engine BuilderParticipant @enginebuilder]

The terminals labeled 123,4 are auxilary contacts and the other 2 will be the coil.

[Les Jones 1Participant @lesjones1]

Hi Daniel,

What Engine Builder says is probably correct. but you need to identify which ones are the coil and which the auxiliary contacts . With your multimeter find the pair (Amongst 1, 2, 3, 4) which has a resistance of maybe 100 ohms or so. (This is just a guess. ) The other pair should show open circuit until you press on the top of the contact assembly when they should show continuity. You will need to confirm the voltage of the coil as it could be used in three different ways. 1 It could be a 415 volt coil in which case it will be connected between phases via the start and stop buttons.

2 It could be a 230 volt coil in which case it would be connected between neutral and one phase via the start and stop buttons. 3 it could be a low voltage coil and fed from a transformer so that the start and stop buttons and interlocks only had low voltage on them.

1 is the most likely, 3 is the least likely. When you have this information I will draw a diagram of how to connect it.

Les

[Engine BuilderParticipant @enginebuilder]

3 and 4 are NC contacts and 1and 2 are NO and used to hold in the coil. The coil connections are the 2 small terminals at the bottom either side of L2. My 1968 Crabtree Electrical Handbook shows this.

[Daniel RobinsonParticipant @danielrobinson12697]

Thanks for the help engine builder and Les Jones 1

Engine builder, I would give my left foot (as I need both my
arms) for a copy of that page. I contacted Crabtree to see if they could give
me a pin out diagram. Unfortunately their records don’t go that far back.

[Engine BuilderParticipant @enginebuilder]

No need cut off your foot Daniel. PM me your email and I send you a scan.

David

[john swift 1Participant @johnswift1]

Hi Daniel ,

 

It’s so long ago I last looked at a direct on line starter like the one you have

I’ve forgot the finer details.

but if you look at the contactor from the other side you should see the thermal overload

rotating the red spindle sets the overload current and pushing it down manually

opens the switch for stop (and reset)

 

you need to confirm you have a 440v coil for 3 phase and not 240v for single

phase. ( should be printed on the coil , they can be bought separately)

 

with the square start switch you need to wire the one phase via the

normally open contact to the coil

then from the coil via the overload / stop switch to another phase

to complete the circuit.

 

without an auxillery contact as on new contactors

I think you will find the start switch is mechanically held down when

the contactor is energised.

 

 

if no one has the info for your contactor

post a picture of the overload and stop switch and

I’ll draw and post a diagram of what I expect the wiring to be

 

John

 

 

 

 

 

 

 

 

[Daniel RobinsonParticipant @danielrobinson12697]

Thank you all for your offers of help on this one and a special thanks to Engine Builder who passed me the pin out diagram for this unit from the 1968 Crabtree Electrical Handbook. Amazing some of the stuff we keep.

[Author]

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