I am not conversant with a ‘caravan mover’ but your mention of live and neutral infers that it is mains powered.

In general it is not necessary to have switches (or relays) in both the supply leads to a load but more information is needed to give sensible and safe advice.

Is the remote control a wired or wireless type?

Ian P

Although it may not be strictly necessary to switch both “hot”(eg mains live, DC power) and “cold” (eg mains neutral, DC ground) lines when using relays my personal preference is always to switch both when connecting accessories.

Even if for no other reason than neatness of circuit diagram and installation with everything going to the input side of the really and everything coming off the output side. If you are using plug in socket relays this also makes it very easy to isolate everything just by pulling the relay from its socket. With mains powered systems its not unknown to get MCB / RCD weirdies when working on a system that has a continuous neutral even though the power side has been disconnected and safely isolated.

Embedded car and motorcycle systems using 12 V DC power are about the only time I use single sided switching relays. Slightly different in that case as there has to be a ground connection for one end of the operating coil anyway.

Clive

I don’t know what sort of ampage the motors take and if your switches would be up to it.

If not, you could put in relays to switch the current, and switches to control the relays. Note, select relays that would be capable of switching the loads.

As you say your not good with electrics do you have a wiring diagram to hand or in mind ? If the motor is a permag then to reverse it you swap the motor connections so it would be safer and easier to do this with relays set near the power source This will keep wires short and voltage drop low. Your switches then only have to switch the coil current and be thin rather than may be 20 or 30A, a stall could easily draw this current. Noel.

Graham says he’s repurposing a Caravan Mover, so I think the answer boils down to how many amps have to be switched.    Here’s an example of the beast (two movers needed per caravan, with one controller):

The circuit shows the movers are powered by a 12Vdc battery, and judging by the size of the wires I guess 10A to 20A.

Fitted to a caravan, there is only one switch fitted in the red positive lead.  But this is an isolating switch and most of the serious switching is done inside the blue/grey controller.  It obeys orders from a hand-held remote.  As the controller is slim, I guess it’s semiconductor switched, not by a relay.  No matter: Graham can switch his motor however he wants, provided the contacts in the switch or relay can cope.

One thing to watch is that many switches are rated for mains AC, which is much less demanding of the contacts.  All switches arc, which burns and tends to weld the contacts, but AC is self-extinguishing, because AC falls to zero volts 50 times per second.   In contrast a DC arc is only extinguished after the contacts move sufficiently far apart.   Thus DC rated contacts tend to be beefier than their AC equivalents and are often spring loaded to open and close faster too.

This double pole example from RS might do what Graham needs – rated at 20Adc.  I’d switch both Positive and Negative leads because if a contact welds, then the other will still open and stop the motor. Safer.  (Switching both Line and Neutral AC lines is avoided because a jambed closed contact leaves the equipment live and dangerous – looks switched off and isn’t.  This safety concern doesn’t apply to 12Vdc.)

High-current DC switches are a little difficult to find, in which case it might be necessary to use a relay, or same thing, a contactor.  (Folk with an electronics background tend to call them relays, chaps who do power tend call them contactors: same difference!)  Relays allow a small or remote switch to control a big current, just make sure the contacts are rated for it.

Any need to reverse the motor?

Dave

This is part of the specifications for the Titanium EGO400

Operating Voltage  12V DC
Avg Current Consumption  25 Amps
Max Current Consumption 76 Amps

Its not clear from the data sheet whether the numbers are for one or two of the motorised units but even if its one (which I think its is) then a switch with substantial contacts is required. The relay that Graham showed a picture of should be suitable as a m/c and sidecar is a lot lighter than (half of) caravan.

Ian P

I’ve always wondered, what is a motor factor?

Confirming Duncan’s post … amongst the multitude of meanings, you will find this:

.

.

MichaelG.

.

Ref. https://en.wiktionary.org/wiki/factor

Ref. https://en.wiktionary.org/wiki/commission_agent#English

Not a term in common use.  To my surprise though, Halfords have a useful range at reasonable prices.

On 19 November 2024 at 08:24 John Haine Said:

Not a term in common use…

It’s a shame when common terms fade away.  When I was a little boy most towns had a High Street full of speciality shops, mostly now destroyed by super-markets, hyper-markets and now internet shopping.   Alas, Haberdashers, Milliners, Tobacconists, and even Greengrocers are no more.

Alway been thus, all change!  My parents used Emporium as a joke word, and Purveyor was half joke, half respectable.  Some of these old names have longer legs than others:  a few Arcades and Galleria about, but Boutiques didn’t last long!  After a brief spell as top buzzword, Discotheque was replaced by Disco,  which took over the world for about 15 years.  Try asking youngsters if they’re going to a disco.  They’ll probably repress their sniggers, just as I did when an uncle asked teenage me if I was going to a hop.

A few weeks ago I had to buy medicine from a Pharmacy.  They may be the last survivor of the old system whereby goods were kept behind a counter, and you had to ask an assistant for what was needed, and nothing was handed over until wrapped and paid for.   I remember a old-fashioned coop where buying meat involved queueing at the butcher counter to order it, after which the butcher sent a ticket through a pneumatic tube to an enclosed booth who handled the money.  Then the customer queued again to pay, and be given a voucher which he took back to the butcher – more queuing.  Only then was the meat handed over!     Pneumatic tubes are still common: big supermarkets often use them to transfer cash from tills to the back-office.

Just started to snow here in Zummerzet!

Dave