Electrical Queries

[Big Jim]

I am just about to start wiring up my IP/Essel/PMR hybrid loco.
Does anyone know what sort of amperes the 12-24v como 30:1 motor will draw?
Basically I was wondering if my 1.4amp stock of layout wire will be up to the job with such a powerful motor?
Do people fit fuses to their locos.
With a Deltang rx fitted and a sound module as well I don't want any problems that would cause the escape of the 'magic smoke'

I don't normally bother with such issues but this is a much more powerful set up than I am used to.

[DLRdan]

If you look on the website there might be a tech sheet which will have the current draw on it.

[Gralyn]

if you don't have it the web site is www.mfacomodrills.com I have a new one still in its packaging and there is nothing about current draw. The current drawn by the motor will be dependant on load, i.e. the work it has to do. it will be higher on a stiff chassis than on a free running one. If your wire is rated at 1.4 amp why not fit a 1 amp rated auto cut out switch ( available from Maplins I believe) They Auto reset so you don't have to keep changing fuses. The other devices you mention will be fed by their own wiring ( or should be) and not on the motor circuit at all.

[Big Jim]

Thanks for the info folks. I should have made it clear that all the components will be on separate circuits. This is all a bit new to me having only messed around with smallish motors and simple circuits before. The only risk being a battery holder going into melt down.

[ge_rik]

I am just about to start wiring up my IP/Essel/PMR hybrid loco.

Do people fit fuses to their locos.

Most definitely! For peace of mind, it's worth investing in one of these - http://www.maplin.co.uk/p/16a-auto-rese ... aker-ak08j

Rik

[Big Jim]

Thanks Rik, I think a trip to Maplins is in order.
Do you wire it into the main battery feed or between the speed control and motor?

[steampig]

Doesn't the speed-controller incorporate over-current protection (of itself) anyway? If not I'd be far more worried of smoking that than the wiring getting warm.

Provided they take the same route (twist them around each other) two wires paralleled will take twice the current of one, although perhaps less elegant than getting in some heavier wire.

[Big Jim]

I have no idea if the ESC has over current protection.
It is one of these...
http://www.deltang.co.uk/rx65b-22-v611.htm

I will email Deltang and find out.

[ge_rik]

Thanks Rik, I think a trip to Maplins is in order.
Do you wire it into the main battery feed or between the speed control and motor?

As close to the battery as possible.

Rik

[steampig]

I have no idea if the ESC has over current protection.
It is one of these...
http://www.deltang.co.uk/rx65b-22-v611.htm

I will email Deltang and find out.

As it says the stall-current of the motor at 100% output should not exceed the controller current rating, it looks like there is no protection (gosh). I understand your caution.

[GTB]

It is one of these...

http://www.deltang.co.uk/rx65b-22-v611.htm

The systems that Tony Walsham at RCS sells here in Aust. are Deltang based, but have considerably better instructions.

http://www.rcs-rc.com/store/PDF/Instruc ... /Rx65b.pdf

You'll notice he uses 3amp polyswitches to limit current in case of shorts. I fit these to my battery controllers and they work well, but take up little space. They are also known as PTC fuses.

Tony has been putting r/c into battery and steam powered large scale models for years and there is a lot of information scattered around his website.

MFA/Como have their motor specs buried deep in their website. You'll need to identify the motor type used by Essell.

http://www.mfacomodrills.com/pdfs/Minia ... motors.pdf

The stall current can be very high, but you should get nowhere near that, unless something jams the gears. I fit light gear covers fabricated out of brass shim to keep dirt out of open gearing for just this reason.

With electrically powered locos., I keep the weight low enough that they will slip at full power. The current required to slip the wheels needs to be within the ESC rating and the circuit breaker needs to be chosen with this in mind.

Regards,
Graeme

[Big Jim]

Thanks again for the advice. While basic wiring I do understand (and can bus systems funnily enough) this modern rc stuff is a a bit of a brain bamboozler.

[ge_rik]

The systems that Tony Walsham at RCS sells here in Aust. are Deltang based, but have considerably better instructions.

http://www.rcs-rc.com/store/PDF/Instruc ... /Rx65b.pdf

You'll notice he uses 3amp polyswitches to limit current in case of shorts. I fit these to my battery controllers and they work well, but take up little space. They are also known as PTC fuses.

Looks like Tony suggests using two fuses; one to protect the battery and the other to protect the receiver/ESC. I've never bothered with protecting the ESC and had no problems (up to now) but it does seem like a good idea. After all the cost of a fuse is considerably less than the coast of a new rx

Also the newer rx65 is rated at 3 amps and so a higher rated fuse can be used than the 1.6A one shown in my post above which I use with the earlier, lower rated Deltang rxs.

Rik

[GTB]

Looks like Tony suggests using two fuses; one to protect the battery and the other to protect the receiver/ESC.

The second polyswitch between the ESC and motor has only appeared on the latest Deltang ESC wiring diagram from Tony. The docs. for his older ESCs only show the one at the battery.

I only have one of Tony's systems and it's installed in a steam loco, so I've no experience of his r/c battery powered systems. My railmotors and 'diesel' have a simple manual speed control circuit.

Graeme