Motor controls, DOL starters etc

[TheCodboy]

Hi all. I'm looking to build myself a rig with a small single phase motor and learn a bit more about motor controls etc. I mostly do domestic and some commercial but haven't much experience with motor controls. I always looks at ways to improve myself and my electrical knowledge. Most DOL starters would be pre wired so i take it there wouldn't be much to be gained from that. So would i be better buying NO & NC Switches, Contactor and overload and building it that way? Also looking for advice with regards to contacts 97/98 on the overload. Again, this is not a job or anything like that, this is solely for the purpose of building a rig to give me a better understanding. Any guidance and advice would be very much appreciated. Thanks

 

[westward10]

Sounds like a good idea then you can see the workings and understand the principles of the control. 97 and 98 terminals are NO (Normally Open) until the relay trips which closes them and could be used to provide a visual or audible warning that the relay has operated. Terminals 95 and 96 are NC and incorporated into the control circuit.

 

[TheCodboy]

Sounds like a good idea then you can see the workings and understand the principles of the control. 97 and 98 terminals are NO (Normally Open) until the relay trips which closes them and could be used to provide a visual or audible warning that the relay has operated. Terminals 95 and 96 are NC and incorporated into the control circuit.

Is there anything else you think I would need the make a start??

 

[westward10]

You could buy a DOL starter complete and deconstruct it with separate NO and NC control switches. You could get some red and green indicators and incorporate them into the control circuit, green for good and running and red for relay fail across the 97 and 98 terminals.

 

[TheCodboy]

You could buy a DOL starter complete and deconstruct it with separate NO and NC control switches. You could get some red and green indicators and incorporate them into the control circuit, green for good and running and red for relay fail across the 97 and 98 terminals.

Thanks. I'll start having a look!

 

[westward10]

If you get a starter with a low enough rated relay you can create a trip situation by just running a kettle through it.

 

[TheCodboy]

If you get a starter with a low enough rated relay you can create a trip situation by just running a kettle through it.

So am I right in thinking that with a smaller starter,the control circuit won't need it's own protection where as once you start getting bigger,the control circuit would have its own circuit protection?

 

[pc1966]

So am I right in thinking that with a smaller starter,the control circuit won't need it's own protection where as once you start getting bigger,the control circuit would have its own circuit protection?

Usually you must have fault protection up-stream, so fuse or MCB, but the overload protection for the motor is covered by the (usually adjustable) thermal trip on the starter.

 

[westward10]

So am I right in thinking that with a smaller starter,the control circuit won't need it's own protection where as once you start getting bigger,the control circuit would have its own circuit protection?

Prewired DOL starters generally don't incorporate circuit protection into the control circuit.

 

[TheCodboy]

Prewired DOL starters generally don't incorporate circuit protection into the control circuit.

So that's due to the smaller amount of demand, whereas something drawing more load,the smaller control circuit will have its own protection yes?

 

[westward10]

So that's due to the smaller amount of demand, whereas something drawing more load,the smaller control circuit will have its own protection yes?

It isn't likely to pose a fault issue due to the nature of the wiring and should the coil fail it is such fine wiring it will likely just rupture like a fuse, that is my personal theory by the way?

 

[TheCodboy]

It isn't likely to pose a fault issue due to the nature of the wiring and should the coil fail it is such fine wiring it will likely just rupture like a fuse, that is my personal theory by the way?

So your saying use the control circuit wiring as fuse wire!! ?

 

[westward10]

So your saying use the control circuit wiring as fuse wire!! ?

I was referring to the fine wire of the hold in coil?

 

[TheCodboy]

I was referring to the fine wire of the hold in coil?

??? Suppose that makes more sense!!!

 

[ipf]

Learn about connecting a 3 phase starter controlling a single phase motor
and make sure it's a 230v coil.
You could acquire and connect, for the sake of it, but overloads would be pointless with such a motor. O/L push button to test, I suppose......but live working, remember.

 

[Lister1987]

I've got a DOL on my rig, next to it is a 3 way 1G switch that will make/break the main live to the motor (1), the neutral (3) or thr hold contact (1-A1).

I get tothe wife to choose a setting and cover the switch, I then troubleshoot it and confirm that I have got the right fault.

 

[ipf]

'Retaining contact' you mean.

3 way! You play eeny, meeny, then? ? ?

 

[Lister1987]

'Retaining contact' you mean.

Hold, retaining....potato potatoe ?

 

[TheCodboy]

I've got a DOL on my rig, next to it is a 3 way 1G switch that will make/break the main live to the motor (1), the neutral (3) or thr hold contact (1-A1).

I get tothe wife to choose a setting and cover the switch, I then troubleshoot it and confirm that I have got the right fault.

Could you take some pictures of how you've wired that please?

 

[ipf]

Hold, retaining....potato potatoe ?

Proper trade talk, mate. Keep learning.
It's not an english language forum. ? ?

 

[Lucien Nunes]

Building a starter from parts will be interesting and rewarding. Embellishents you might like to add could include a remote button station with local/remote enable switch, or a hand/off/auto switch with an input for a sensor such as a float switch. The next level of complexity would be a reversing starter with limit switches etc operating on ELV control.

Spec the parts, draw the mechanical construction and the schematic, build it like a proper panel.

It's worth getting a book or two on the subject before getting stuck in, because there are some subtleties that you can't learn just by wiring things up.

 

[TheCodboy]

Building a starter from parts will be interesting and rewarding. Embellishents you might like to add could include a remote button station with local/remote enable switch, or a hand/off/auto switch with an input for a sensor such as a float switch. The next level of complexity would be a reversing starter with limit switches etc operating on ELV control.

Spec the parts, draw the mechanical construction and the schematic, build it like a proper panel.

It's worth getting a book or two on the subject before getting stuck in, because there are some subtleties that you can't learn just by wiring things up.

Any recommendations on books?

 

[Lucien Nunes]

Sorry, can't suggest any specific titles. Some of the books I learmed from are 100 years old now and differ from modern practice in lots of details, although the principles haven't changed much.

 

[ipf]

There are plenty. Something basic for starters (no pun). My learning books aren't available these days.
It's a very wide and complicated subject, certainly for beginners.
Even beginning, before you start 'speccing' materials, read and get to know fundamentals. You can read about motor control but, starting from scratch, you'll need some help. It could be dangerous, remember, so building live rigs, at home, I would not recommend.
A workshop of some sort, maybe?
Good luck.

 

[TheCodboy]

There are plenty. Something basic for starters (no pun). My learning books aren't available these days.
It's a very wide and complicated subject, certainly for beginners.
Even beginning, before you start 'speccing' materials, read and get to know fundamentals. You can read about motor control but, starting from scratch, you'll need some help. It could be dangerous, remember, so building live rigs, at home, I would not recommend.
A workshop of some sort, maybe?
Good luck.

I've got my outhouse which is where I'll be doing it. Closest I'll get to a workshop!!

 

[TheCodboy]

There are plenty. Something basic for starters (no pun). My learning books aren't available these days.
It's a very wide and complicated subject, certainly for beginners.
Even beginning, before you start 'speccing' materials, read and get to know fundamentals. You can read about motor control but, starting from scratch, you'll need some help. It could be dangerous, remember, so building live rigs, at home, I would not recommend.
A workshop of some sort, maybe?
Good luck.

I understand where your coming from, like I say I'm not a novice to electrical work,I do mostly domestic & some commercial stuff.

 

[TheCodboy]

There are plenty. Something basic for starters (no pun). My learning books aren't available these days.
It's a very wide and complicated subject, certainly for beginners.
Even beginning, before you start 'speccing' materials, read and get to know fundamentals. You can read about motor control but, starting from scratch, you'll need some help. It could be dangerous, remember, so building live rigs, at home, I would not recommend.
A workshop of some sort, maybe?
Good luck.

And this is also a reason why I'm trying get a better grasp of this type of electrical work. I think if I have to spend one more day crawling around in someone's loft I'm gonna genuinely crack up.

 

[ipf]

I understand where your coming from, like I say I'm not a novice to electrical work,I do mostly domestic & some commercial stuff.

Ok mate.
Have a look at 'HSE electrical' on YouTube 'dol wiring diagram'. From what I can see, they describe pretty well for single and 3phase.

 

[ipf]

And this is also a reason why I'm trying get a better grasp of this type of electrical work. I think if I have to spend one more day crawling around in someone's loft I'm gonna genuinely crack up.

Might take a bit of a while...but if you catch on, who knows.
Variable speed inverters next.....a bit different to all the different types of starting methods employed in the past.

 

[brianmoooore]

So am I right in thinking that with a smaller starter,the control circuit won't need it's own protection where as once you start getting bigger,the control circuit would have its own circuit protection?

Self contained DOL starters don't have any lower rated fusing for the control circuit, but once you start adding external start and stop switching, it's usual to add fusing for them, assuming the breaker suppling the starter is too big for the wire used for the control circuit.
Often a 'slidelock' type fuse is used, suspended by the wiring inside the starter case.

 

[Lister1987]

Could you take some pictures of how you've wired that please?

 

[Lister1987]

Blue and brown at top are from th CU/MCB

 

[TheCodboy]

Ok mate.
Have a look at 'HSE electrical' on YouTube 'dol wiring diagram'. From what I can see, they describe pretty well for single and 3phase.

I found this one (amongst many others). What do you think of this wiring? I believe that the maker of this video is from overseas, and i know some of our electrical practices do differ.

 

[David Prosser]

RS PRO DOL Starter, DOL, 0.75 kW, 240 V ac, 1 Phase, IP55 | RS

uk.rs-online.com

there is an installation instruction manual in the Technicle reference section with wiring diagrams on for single and three phase DOL. RS put loads of informantion on there site it worth getting use to using it.

 

[TheCodboy]

RS PRO DOL Starter, DOL, 0.75 kW, 240 V ac, 1 Phase, IP55 | RS

uk.rs-online.com

there is an installation instruction manual in the Technicle reference section with wiring diagrams on for single and three phase DOL. RS put loads of informantion on there site it worth getting use to using it.

Nice one,thanks!