DOL/Remote control wiring challenge! (UK) Who's in?

[ThomasJ Graham]

Hi all,

I've had good luck from the splendid folk on this forum before so here's hoping for the same again....

I've got a three phase dust extraction unit that currently starts with a DOL unit. It's wired like this:
Extractor DOL wiring.JPG

I've got a radio controlled remote control unit (eMylo) that has a live and neutral in and live and neutral out (240v). I understand that you can use it to operate the contactor. I don't know if you can use it with the start/stop buttons as currently wired and with the thermal overload protection still working.

Anyone out there know what they're talking about who might be able to advise?

Thanks!

Tom

[Jim Becker]

Is the control side of the contactor rated for 240v so you can use the RC switch you mention? That's key to the solution...

[ThomasJ Graham]

Is the control side of the contactor rated for 240v so you can use the RC switch you mention? That's key to the solution...

Thanks for the response Jim.

The coil states that it is 380-415V. The three supply live wires are 230V each so I assume that's what the one live that is currently controlling the contactor is: 230v. I'm only just working this stuff out though so may be confused!

[Mike Kreinhop]

There's something wrong with your drawing. You don't show the A2 connection, which is the other side of the coil. I think you are also showing the connections to the auxiliary contacts, 95 and 96, incorrectly.

If the coil is rated for 380-415V, then it is supposed to be connected to any two of the phases, not a phase and neutral. In Germany, and I assume the UK, residential 3-phase power is 230V phase to neutral and 400V phase to phase. If your coil is designed for 400V, then I don't think your eMylo remote will work. If you want to use it, then you will have to find another relay with a coil rated for 230V and contacts rated for 400V.

[Rod Sheridan]

There's something wrong with your drawing. You don't show the A2 connection, which is the other side of the coil. I think you are also showing the connections to the auxiliary contacts, 95 and 96, incorrectly.

If the coil is rated for 380-415V, then it is supposed to be connected to any two of the phases, not a phase and neutral. In Germany, and I assume the UK, residential 3-phase power is 230V phase to neutral and 400V phase to phase. If your coil is designed for 400V, then I don't think your eMylo remote will work. If you want to use it, then you will have to find another relay with a coil rated for 230V and contacts rated for 400V.

Agreed Mike except I think his auxiliary contacts are 13 and 14...............regards, Rod

[Frank Pratt]

Yes, 13 & 14 is an auxiliary contact that is serving as a holding contact. 17 & 18 is the start push button, 95 & 96 is the stop button & there should be a jumper from 14 to the other coil terminal (A2)

[Malcolm McLeod]

There's something wrong with your drawing. You don't show the A2 connection, which is the other side of the coil. I think you are also showing the connections to the auxiliary contacts, 95 and 96, incorrectly.

If the coil is rated for 380-415V, then it is supposed to be connected to any two of the phases, not a phase and neutral. In Germany, and I assume the UK, residential 3-phase power is 230V phase to neutral and 400V phase to phase. If your coil is designed for 400V, then I don't think your eMylo remote will work. If you want to use it, then you will have to find another relay with a coil rated for 230V and contacts rated for 400V.

Yes, 13 & 14 is an auxiliary contact that is serving as a holding contact. 17 & 18 is the start push button, 95 & 96 is the stop button & there should be a jumper from 14 to the other coil terminal (A2)

^^+1 (not that these gentlemen need validation!).

Thomas, I am NOT familiar with the eMylo remote, but from your description and drawing, it sounds as if the Emylo has wetted contacts and I suspect is poorly suited to this application - even if its voltage rating matches the voltage of your coil AND supply. I don't see the required neutral wire in the schematic, and I'd bet this allows the remote's logic and radio to power up. So I think you'll need a neutral regardless of your path forward?

Additionally, you would need to either remove the existing start/stop switches (and just use a remote - not necessarily the one in-hand). Or, install a Hand-Off-Auto (HOA) switch.

The HOA's 'Hand' contact would install (and break the circuit) between L3 and 96. So when in 'Hand', the start/stop switches work as designed.

The HOA's 'Auto' contact would also get power from L3, but send it to the remote output contact when selected. The remote then completes the circuit to O/L relay to A2 (coil).

In my humble opinion, you need a remote with dry contacts rated for the coil's voltage and ampere draw. Then make a decision about the existing switches:
- Keep Start/Stop as a manual back-up? = get an HOA switch.
- Don't need them? = de-terminate them, ditch the HOA idea, and wire the remote's output contacts so as to directly switch power from L3 to O/L relay to A2.

Edit: Re-read the OP, and the overload relay should be just fine as-is, regardless of the control scheme/wiring you use. There is something missing here as well tho' - - I have to assume the wire from 14 to A2 must pass thru the contacts on the O/L relay. If so, factor that in....

[ThomasJ Graham]

Yes, 13 & 14 is an auxiliary contact that is serving as a holding contact. 17 & 18 is the start push button, 95 & 96 is the stop button & there should be a jumper from 14 to the other coil terminal (A2)

Absolutely, yes. I missed out 14 to A2 because I didn't see it hidden underneath the bottom of the contactor! This is more like it now.
Extractor DOL wiring 02.JPG

So it seems having the 415V coil is going to scupper me if I do want to use this radio device.

I might try a 240V coil with a thermal overload and -- I think this is right -- the 240V live from the radio switch to the 95 contact, 96 to A1, and the radio switch neutral to the other side of the coil, A2. Would this be possible while maintaining the start and stop switches wired as described by Frank??

Malcolm, I need to do a bit of reading up to fully understand what you're say there! But I'm heeding your wariness about the inappropriateness of the switch. The supply is three phase and the control would be single. It sounds like you're suggesting this is a problem.

Thanks all for your contributions. I'm learning....

[Malcolm McLeod]

So, I'm confused.

On your schematic:
Is 95/96 your aux contact on the O/L relay? Or, is it a Stop PB? "95/96" is typical OL numbering in IEC schematics. (Don't use IEC everyday, so took a while to sink in.) In my previous post I took it to be the Stop.

If 95/96 IS the O/L, then how do you stop this juggernaut? Start PB at 17/18 pulls in coil, closes holding contact (13/14), and only way to stop is kill power.

If 95/96 IS NOT the O/L, but in fact is the Stop, then you have no proper O/L protection.

I realize you hope to change some if not all of the existing wiring, but want to make sure you understand the implications. Sounds like you wish to keep the existing manual start/stop, and I'll still advocate that to do so - properly - requires adding an HOA.

I was curious about the eMylo, so looked them up. They have several models, but all I saw are in fact wetted contacts, require a neutral, and the logic/radio section use parasitic power to operate.

Sorry to be a skeptic, but please make sure you are up to this work. Arc flash boundary on your starter is ~850mm from quick look at a table - not a proper analysis, but might get you seated in the right pew. Saving L200 on a DIY remote is a lousy ROI if the house burns down or an arc takes your little finger off. Be careful.

***********************
Edit: I believe the following schematic is either what was provided as part of the OEM's 'canned' starter package, or maybe what you intend to draw? Either way, this is the correct way to do DOL with a full voltage coil (i.e. rated for phase-to-phase voltage). I'd advise starting from here, and determine if or how to incorporate a remote.
mtrStrt3ph.JPG

[Malcolm McLeod]

So found a few minutes to scribble this:
mtrStrt3ph-mod.jpg
It should do what you are asking. Cost will be the HOA switch, and a new 230V coil (220V? ...not sure of the UK standard) for the 3ph contactor, no need for an all new unit. I think the eMylo will handle the loads required here and operate the coil - - but I'm guessing, since I found NO instructions or documentation online (big alarm bell for me). For HOA, get something of common manufacture and size as the existing operators to keep the OEM 'feel' - should be about $22-$25.

...No warranty offered or implied!

Please be careful.

*****************
To SMCers, I decided to edit this before the opportunity 'expires' - - Not sure if we've lost the OP (need to give him more time), but if you're interested in a really low cost remote for a tool or DC, this runs $14-$18 w/ 2 key fobs and may be available in 120VAC. But it's cheap. What info I found on it doesn't give me the warm fuzzies; just feels like China searching for the bottom rung of the marketing ladder. But it's cheap. It's easy to re-do the above schematic in 1ph / 3ph / 120V / 230V / 480V or even a 24VDC control circuit - but since the eMylo uses wetted contacts and operates off of parasitic power, the eMylo selected must match the control power voltage. But it's cheap. Yell if you're interested. Enjoy. Cheaply.

Some editorial content may be present in this post.

[ThomasJ Graham]

Hi Malcolm, you haven't lost me! Just trying to find the time to compose a coherent message that responds your many useful points with some degree of understanding.

Re. Safety: I hear you! I'm trying to get a sense of how you might do this and will probably get an electrician to go over my plans before doing anything silly. I've got a fair regard for my own health as much as I do like to learn through doing.

The drawing I made was my interpretation of the current functioning DOL with a push button start and stop. The stop button is a part of the overload unit and I thought that was a NC switch between 95 and 96. Fwiw, the starter is an Eaton ADS8.

I would definitely like to keep the function of existing switches but don't know quite what the HOA setup looks like in practice. I'm going to take what you've said and run it past my very hard to get hold of electrician and see what he says. If I get this thing working I'll be sure to post images here.

Thanks again for your help!

[Malcolm McLeod]

...
The drawing I made was my interpretation of the current functioning DOL with a push button start and stop. The stop button is a part of the overload unit and I thought that was a NC switch between 95 and 96. Fwiw, the starter is an Eaton ADS8.
...

mtrStrt3ph-ADS8.JPG
I looked at Eaton's schematic for the ADS8, and the Stop button is indeed mechanically integrated with the O/L. I've never seen this done (I really should get out more!), but will assume it saves a bit of cost.

If you simply ignore the Stop PB in my last schematic, the eMylo should integrate in the same manner/position. There are several options with the HOA, but the one I show keeps the magnetic 'safety' (anti-restart) - at least for the 'Hand' position. Your guess is as good as mine, as to how the eMylo will handle a power off >> on transition while in 'Auto'.

Eaton's pictures don't show the guts and I'm guessing it's rather space efficient, so it does look like you would have to place the HOA switch somewhere other than 'in' the face of the ADS8 - maybe in a small, single button enclosure with a close nipple between the ADS8 & the HOA enclosure? You'd need 3 conductors to interconnect.

[Bill Dufour]

DOL? in education that means daily oral langauge. So you have to yell at the machine to turn it on?
Bill D.

[Malcolm McLeod]

DOL? in education that means daily oral langauge. So you have to yell at the machine to turn it on?
Bill D.

Direct-on-line, I believe - tho' yelling may work too. I always called it 'line start', or 'across-the-line start'.

[Bill Dufour]

Does that mean it senses current flow and switches on the collector when a dust making machine is started up?