3 Phase Stop Start Switch

[MUFC1999]

Hi all.

Had a call today to go and swap a stop start switch. The switch is used to control a car ramp in a garage and the old one had stopped working. The mechanics Brother is a spark but is now on holiday and unreachable.

The old switch had already been removed and it's replacement was waiting for me when I got there.

All I had in front of me was a 3 core swa and a 3 core flex to the motor. Connected it all up but the switch will not work from the start button but will if you depress the switch on the front of the contactor. There was a lead connected to L2 which looks like it has to be connected elsewhere.

I'll try and get a picture up if that will help.

Any ideas? I'm suppose to be going back tomorrow to hopefully get it sorted.

 

[telectrix]

probably goes to one side of the coil. if it's a 415v coil, one side is perm to 1 phase and the other end energised by the start button

 

[Guest123]

Have you connected anything at A1&A2 (coil) terminals???

 

[MUFC1999]

Have you connected anything at A1&A2 (coil) terminals???

No, I just connected straight to l1, l2 and l3, then same again on the other side of the contactor. It's a long time since I even looked at 3 phase.

 

[telectrix]

look at the terminals marked A1 and A2. they should each have a wire in.

 

[Engineer54]

Hi all.

Had a call today to go and swap a stop start switch. The switch is used to control a car ramp in a garage and the old one had stopped working. The mechanics Brother is a spark but is now on holiday and unreachable.

The old switch had already been removed and it's replacement was waiting for me when I got there.

All I had in front of me was a 3 core swa and a 3 core flex to the motor. Connected it all up but the switch will not work from the start button but will if you depress the switch on the front of the contactor. There was a lead connected to L2 which looks like it has to be connected elsewhere.

I'll try and get a picture up if that will help.

Any ideas? I'm suppose to be going back tomorrow to hopefully get it sorted.

A picture or two are worth a thousand words, ....or so they say!! Yes some pic's will be helpful...

 

[Guest123]

No, I just connected straight to l1, l2 and l3, then same again on the other side of the contactor. It's a long time since I even looked at 3 phase.

It's the A1&A2 terminals that energise the coil that holds the contactor in so the machine runs without you having to keep your finger on the start button.

Check the coil rating 24V, 110V 230V 400V etc, more than likely 400V in this case and connect accordingly.

Below is a diagram of a 230V coil circuit, if yours is 400V, substitute the 'N' connection at A1 for a different phase to the one at A2.

 

[MUFC1999]

I think a1 was behind L1, there was a terminal behind NO to the right of L3 and the same on the load side (a2 ?). Nothing is connected to a1 and what I'm guessing to be a2.

Blue Red and Yellow were connected in the isolator that way round.

Just realised that link didn't work. Having a mare here!!


http://s1-04.twitpicproxy.com/photos/large/433623139.jpg

http://local.twitpicproxy.com/web4/...f63832490a7b96c702b1585c5.4ea858b0-scaled.jpg

 

[Knobhead]

From what I can see (my bad eyesight is legendary) you have no supply to the control at all. You’ll have to follow Lenny’s drawing wire by wire.

 

[Darkwood]

As i understand it he said its a car ramp it should operate with Dead man controlling in that if your finger is taken off then it stops, the wiring diagram Lenny has supplied has a retaining circuit in it to hold the coil in which in this situe is probably wrong, first question is whether the ramp is hydrolic or not if so then you will have a one direction motor, if its fully mechanical then the motor will have forward/reverse control. So need more info first please. In a word does this contactor just energise the ramp controls in which case i apologise lenny:disguise: lol or does it actually raise the ramp itself when pressed with seperate mechanical release to lower.

Just clocked eyes on your photo (1) cant download second one, where is the overload protection for the motor???? It may be the control system requires updating to meet modern standards in which case replacing the unit to a all in one start stop unit but again need to know how the ramp stops when its at high point (limit switch ????) etc.
The jist of my post is the old system and control need assessing to see if it meets requirements and by the looks of it requires modernising and upgrading for safety reasons which is probably a job for someone with more experience.

 

[Guest123]

I cant see 2nd pic either.:dunce2:

As DW has said, you appear to be missing an overload, was there one fitted to the old unit???

 

[MUFC1999]

As i understand it he said its a car ramp it should operate with Dead man controlling in that if your finger is taken off then it stops, the wiring diagram Lenny has supplied has a retaining circuit in it to hold the coil in which in this situe is probably wrong, first question is whether the ramp is hydrolic or not if so then you will have a one direction motor, if its fully mechanical then the motor will have forward/reverse control. So need more info first please. In a word does this contactor just energise the ramp controls in which case i apologise lenny:disguise: lol or does it actually raise the ramp itself when pressed with seperate mechanical release to lower.

Just clocked eyes on your photo (1) cant download second one, where is the overload protection for the motor???? It may be the control system requires updating to meet modern standards in which case replacing the unit to a all in one start stop unit but again need to know how the ramp stops when its at high point (limit switch ????) etc.
The jist of my post is the old system and control need assessing to see if it meets requirements and by the looks of it requires modernising and upgrading for safety reasons which is probably a job for someone with more experience.

When the switch is pressed the ramp goes up, let go and the ramp stops. It's hydraulic to lower it so doesn't have a reverse. That's the basics of how it should work. The old controls were thrown away so I can't refer back to them.

 

[netblindpaul]

So "dead man's switch" it is then.
Don't wire in a retain to the contactor coil circuit.

 

[MUFC1999]

Sorry to sound like an idiot but can you give me a quick guide on what to connect where.
Think I've fried my brain trying to get my head round this.

 

[netblindpaul]

MUFC,
This depends on the exact parts you have, normally 3ph supply to 1, 3 & 5, (L1, L2 & L3) motor to 2, 4 & 6 (T1, T2, & T3) on the output of the O/L.
As far as the control goes it could be a few things, though if dead mans switch, no real need for stop though for completeness it would be good to connect so, if 400V coil then L1 to one side of stop button, other side to one side of start button other side of start button to say A2, say L2 to A1.
HOWEVER, as you are replacing the starter then you must ensure that as the designer the machine complies with current statute law, this may not be achieved by my simple explanation above.

 

[GLENNSPARK]

he Should have left it alone until you came to sort it. I may be wrong here but those wires he left....could any of these have become energised if someone had switched something without realising it?....If thats so then that makes him a dimmer and shouldn`t be sparkying.....correct me if i`m wrong though........

 

[MUFC1999]

he Should have left it alone until you came to sort it. I may be wrong here but those wires he left....could any of these have become energised if someone had switched something without realising it?....If thats so then that makes him a dimmer and shouldn`t be sparkying.....correct me if i`m wrong though........

Everything was left safe and locked off.

 

[GLENNSPARK]

Everything was left safe and locked off.

No probs mate ...I`m not the leccy police (nor wish to be) it just seemed like a potential thats all mate...

 

[Darkwood]

Only other thing to mention is what stop the motor riding up too far and jamming (not in a bob marley sense) or damaging the ramp, is there a physical disconnector of the motor like a 3phase lever switch or is it a limit switch to be tagged into stop circuit, sounds doubtful for the latter as its got 400v control and really should have a lower voltage exporting out to limit but nothing supprises me any more with old dodgy machinery.
So as a recap... we have a contactor Dol with no overload protection a 400 3phase flex to motor missing adequate mechanical protection and uncertainty over the safety system if one exists of the limit switch to halt the motor at full height etc etc ... kinda get a feeling you should leave this well alone with your experience, the minute you make a alteration or replace a major part of the electrics you invariably become responsible the the machine/ramp you commision on completion is safe to use.
Havent even mentioned a E.stop circuit on far posts of ramp in case someone out of sight is in danger :bobby:

 

[Darkwood]

@MUFC1999 dont you get the feeling that what should be a simple contactor change has turned into a Health and Safety nightmare , the problem here is the owners usually operate this gear in the knowledge of its lack of safety and dont often want to pay for a re-hash of the electrics to bring upto date.

Now the question is do you leave after making your repair or do you explain you cant repair it and will need a control system overall to make it safe to use....
One method make you a quick buck but also leaves you open for liability if an accident occurs, the other way you made a risk assessment did your upgrade and walked away with confidence that the operators have the protection required related to the risks involved in working around and using the ramp.