DOL Motor starters

Hi All,

I will sound like a simpleton asking this, but there we are!!

You know an "ordinary" motor starter, the sort of thing in a tin box with red and green buttons and a "built in" no volt release.

Is it possible to mount a separate contactor in series with this [as the starter will then retain its NVR and overcurrent functions] to enable remote mounted buttons to be used, and also to incorporate, as well as an "on", and obviously an "off", a "jog" function too??

I ask this because i have an Elliott shaper that i fitted with a single phase motor years ago, only now i want to re-fit it with a three phase one, only i threw away all the original switchgear.........

The motor is a 3HP [say 2.5KW] three phase one. Can anyone recommend a suitable contactor and other bits to achieve what i am trying to do!! [Part numbers from the RS catalogue would be great!!]

Thanks all!!

john..

You can mount as many stop starts as you like - no extra contactor required either. Just remember the start contacts are all in parallel and the stops in series.

Just wire the stop & start buttons in series/parallel respectively with those in the existing starter.

As you are not using this in a business undertaking this will be fine.

Give me the FLC off the rating plate on the motor & we can size the O/L, can do it approximately without, but it is better to have it.

Also don't buy from RS you have a Total in Newport use them, you'll get Schneider kit there much cheaper than RS & better than the tat they sell in CEF.

However, I can get you an RS part number later, just remind me!

you dont need an additional contactor, you can alter the control wiring of the one you have

just make sure there wont be any danger to anyone near the machine when it starts. other regs may apply, but this sounds like a home project?

I'm with you on the not using RS Sidey, very expensive. But schneider control gear all the way IMO.

I'm with you on the not using RS Sidey, very expensive. But schneider control gear all the way IMO.

Click to expand...

as shocking as this may sound, there are a few things i do get from RS because they are cheaper than elsewhere!

As above.

The "jog" function is a little harder. For that you want to disable the hold-on contact.

So put an on / off switch in series with the hold on contact, then when that switch is open, the start button will function as "jog" and when that switch is closed, the start button will be a normal latching start function.

start/stop/inch was a requirement on the old AM2

here's the wiring diagram from it

Tis true Andy, I have had kit cheaper from RS, but Schneider controls are not one!

I was just thinking about the NO/NC on a single button to implement the jog function, I have never done the AM2 though!

There is a fault on that circuit for compliance on "dangerous" machines though.

This would not be part of BS7671 so would not be considered under the AM2 really.

I would consider a shaper a dangerous machine!

Plus it would not comply with BS EN 60204-1 anyway as it is supplied direct off the mains with no control transformer.

Dont buy Schneider its French Tat !!!!Just dont do it - The countrys fine but the rest including the locals is not worth the hassle !!!!

---------- Post Auto-Merged at 14:52 ---------- Previous post was made at 14:48 ----------

John

Have you a budget ?

I can do you a cad drawing and then you could buy the bits separately (box, contactor, auxilliaries, mpcb, terminals etc) and wire up a small starter panel for the Shaper

We could include a proper safety relay for the e-stop with a feedback loop (depending on your budget)

May help with some experience of a bit of small panel work and wiring one

I can chuck in a bit of Tri-Rated and numbers and ferrules etc (anything to stop you buying french rubbish :slap )

---------- Post Auto-Merged at 14:56 ---------- Previous post was made at 14:52 ----------

I have probably got a contactor and mpcb kicking around. whats the motor name plate details ?

---------- Post Auto-Merged at 15:01 ---------- Previous post was made at 14:56 ----------

I have probably got a contactor and mpcb kicking around. whats the motor name plate details ?

Click to expand...

going a bit OTT there!

if you do make drawings i wouldnt mind having a look at them

and apprentice87, if you do make your own panel etc, dont forget the pics

start/stop/inch was a requirement on the old AM2here's the wiring diagram from it

Click to expand...

That's essentially what I was trying to describe, but implemented much better by combining the switch that disables the hold on, with the jog button.

Tis true Andy, I have had kit cheaper from RS, but Schneider controls are not one!I was just thinking about the NO/NC on a single button to implement the jog function, I have never done the AM2 though!

There is a fault on that circuit for compliance on "dangerous" machines though.

This would not be part of BS7671 so would not be considered under the AM2 really.

I would consider a shaper a dangerous machine!

Plus it would not comply with BS EN 60204-1 anyway as it is supplied direct off the mains with no control transformer.

Click to expand...

This would depend on what controls are included in the stop circuit and what protection they had.

If there are no controls external to the starter enclosure then what`s the problem?

Not quite sure what you are getting at Prof, however, there are limits upon the number of "devices" within a circuit no matter what the protection is before a transformer is required.

Also, there is a remote stop/start/inch push button station, if this is not mounted on the "machine" itself, then you would have to comply with 60204-1, no matter what if you are looking to comply with statute law.

There is NO distinction between fitting control circuit protection and having a transformer fed supply.

You'll have to explain your points a little more for me to follow your thoughts.

Hi all,

Oh wow!! thanks for all the help and advice!! Was not expecting all that!! Sorry for being slow to reply, having a few problems at the moment....Anyway. i will try to take one point at a time;

Hi Paul and Revjames,

I never knew i could just wire in addition stop starts!! thanks for that!! As to FLC [for sizing motor overload protection, I have not got a replacement motor to go on it yet, but it will be a 1450rpm 3hp one. I am going to try to get a motor as near as possible to the original, so it will not be one of these super efficient modern ones! an ancient Newman or the like if i can!

Yes they have got a "Total" in newport, and very good they are too!! It is a lot easier for me to use RS though, they are amazingly, quite cheap on some things, but mega pricey on others!!

Hi Andy,

Yes, this is a home project! When i say "remote control" of the starter though, i do not mean from ten yards away..On a shaper, usually, the electrical gubbins is all mounted safely out of the way "round the back" as it were, and next to the operator of the thing is a little box with just the three buttons, go, stop, and jog or inch.

Hi ProDave,

Yes, as you say, the jog function is a little harder, not sure how to arrange this at all...

Hi Canoe,

No, i have not really got a budget.. do not want to spend fortunes, but i do love my machines, errrm toys!! so i would like to get it right and do a nice job!!!

A drawing and a list of bits would be great if you could!!

I do not think i need an emergency stop as such, because as Paul says, yes a shaper is a VERY dangerous machine [if you are silly] but, it will have your hand off long before you ever get as far as the emergency stop button!!!

Hi Andy,

Yes, whatever i build, i will of course post pics!!!! Keep you all amused!!!!

Thanks all

john...

john,

The control gear will be cheaper in Total than RS.

You should have an e-stop even if it is to ensure that in the event of a single fault the machine does ot restart on the use of the stop button.

Remote controls would not eb "on the same machine" really.

If you have 1 motor, one starter and one set of buttons you can use "simple" control even under 60204-1.

Wire the stops in series with the motor overload, wire the starts in parallel with the NO aux retain contact and Bob's your mothers brother.

Ignore the paddler with his references to French rubbish, he loves Vin Rouge!

He is not a fan of Schneider kit.

He prefers kit from Ze Fazerland, i.e. Siemens!

Trouble is round here not many apart from Routeco, & they are expensive, unless you get to know them and get reasonable discounts.

Jog can be done with a jog/run switch or with an no/nc button.

I prefer the switch.

Thing is it depends on which way you want to play it?

Do you want to try to build it to meet "correct" requirements for experience, or just to work?

'Nuff for now

Hi Paul,

Oh, definitely the "proper" way! Not only will i learn a lot, but the machine will be safer.

I will tell you a little story.....

Only a few months ago i was playing about with a miller. [As you do!!]

I pressed and released the "jog" button, but the machine kept running.... I just thought "I am sure I pressed the "Jog", oh well, must have pressed the wrong button...

However, I have now learnt, that, if you wire up a "push button" NO & NC jog switch in the "simple" way, that, when you release the switch, if it returns to its "resting position" for want of a better term, fast enough to beat the auxiliary contacts in the contactor opening, then the machine will continue to run.....

Apparently what i need, is to control the Jog function through a separate relay to "separate" the two functions [latch and jogging]

Not entirely sure this jogging lark, is entirely safe..... What i do at present, is i have removed the guards from the machine drive belts, and when setting the machine, do what anyone with a brain would do, and pull the machine over by hand at least one revolution to make sure that there are no "clashes" if you like..

I know the health and safety people would have a fit, but if you are dull enough to go round the back of the machine and stick your hand in the drive belts, then, sad to say, you would not last 5 minutes round the "working end" of a shaper anyway!!!!!

I know it would be simpler just to fit a "jog" selector switch, but i just KNOW that i would forget to switch to jog, hit the button, and 2 seconds later the machine is scrap......

What i think i will do though, in the spirit of the forum, is to have a go at designing my own system, and post the design on here for critical appraisal as it were!!!

Lot more difficult than just asking the experts, but i will learn more too!!!!!

john...

I was working on an interestin machine today - a Crypton Triangle brake tester. One side of the system not giving enough braking force so was asked to attend. Took the back off the machine and my jaw dropped at the craftsmanship of all the fine control wiring, relays contactors etc. maust be a 1960's machine by the look of it. Turned out to be the star delta controls on one of the motors not changing over. Looks like I will be rewiring the machine soon.

Pics Rev!

I bet it's lacing?

I Thought you would want photos. Lacing has been replaced with cable ties. It was installed about 5 years ago judging by the brown black grey cables. Needs some TLC as its becoming unreliable.

Dont suppose anyone knows where I can get a drawing?

I was working on an interestin machine today - a Crypton Triangle brake tester.

Click to expand...

Only superman could fix that.