24V Speed Controllers

[jackrae]

Anyone any experiences (good or bad) of the commercially available 24volt speed controllers for electric locos, available in UK

As far as I can determine, main UK suppliers are Parkside and 4QD

I'm looking to rig up a 71/4" loco with 4 off 600w motors, though will only consume about 1HP (say 750w total) under load. These figures are based on actual experience so should be fairly reliable. Configuration will be one motor per axle, fitted in parallel with wheel axle and located between wheels as per mainline traction practice, with the motors driving a 4:1 open reduction gear. Motors are PM units and appear to be very well built - sourced from an electric scooter supplier. Photos and details available to those interested.

I reckon I need something capable of handling about 200 to 300A and as far as i can determine its a toss-up between a 300A 4QD model or a pair of Parkside 100A models. I also want reverse and regen braking features. Both makes can drive multiple motors in parallel so it's either all 4 on a 4QD or 2 motors per controller if choosing Parkside.

What I'm really interested in is the robustness - to electrical abuse - and the reliability of each make. When splashing out around £400 or so i don't want something liable to dissappear in a cloud of blue sparks if ,say, the battery inadvertantly disconnects itself whilst running.

many thanks
jack

[the_viffer]

If you are planning on drawing only 800W then I'd question whether you need to use a 7.2kW (24V 300A) controller. The actual motor rating is not terribly important being in part a measure of internal resistance and in part of how much abuse you are prepared to inflict on the motor in the form of heating.

I run a couple of 5" gauge electric locos. One has 6 motors rated 150W at 12V and another 8 of the same. I run them at 24V so my overall power rating is rather more than what you plan to draw. The 6 motor unit has a 4QD 120A (I think) controller and the other has 2 of them linked together master and slave. I've used 2 controllers on the 8 motor loco since it is an 0-6-0 + 0-6-0 and I can link across the chassis with thin control wires rather than thick power cables.

Lack of power is not a problem with either of these locos: lack of adhesion is and they slip and slide. I believe the problem can be reduced by carefull adjustment of the springing.

Modern 4QD units are pretty bullet proof in my experience and are safe against polarity reversal and most other abuse. No doubt they can tell you what will happen if a lead comes adrift.

The 4QD website contains lots of information: possibly too much. It is well worth a look.

Both the Parkside and 4QD owners will respond helpfully to queries. The 4QD chap can be a little gruff at least with fools like me if the info is on his website even if it can be difficult to find but he certainly knows his stuff

[greasemonkey]

Have a chat with the folks at Cromar White. They had a clever electronic controll module on display this year at Sinsheim which from memory was reasonably priced and fairly idiot proof with the built in option of a low power setting for young/learner drivers.

Andy

[the_viffer]

I'm somewhat surprised to find that Cromar White (with whom I was once in negotiation with a view to buying them) are into controllers. There is no mention on their website (which seems substantially unchanged since the Adrian Sant days) of such things but I'd be very glad to have further and better particulars of such a product if anyone has any.

[greasemonkey]

HI All
After a bit of hunting this evening I have found the information that I picked up from Cromar White at Sinsheim and made it into a PDF file. If anyone wants a copy then drop me a message via this board and I'll email it to you.

Andy

[jackrae]

copy of info please
regards

jack
[e-mail]

[jackrae]

Thanks to those who commented

Must admit, the Cromer White gear appears to be quite expensive when compared against 4QD for equivalent power rating. Of course the technology may be entirely different and it would be unfair to compare apples with oranges.

On basis of cost, and past experiences, the ever important factors, I've opted to go for a 4QD-300 controller. Yes it is probably oversized and therefore over-priced for the application but I believe in making allowances for the unintended endeavours that others will make to destroy whatever you supply them with.

Time will tell if I've made the correct choice

regards
jack

[the_viffer]

I'd be glad of a copy of the pdf too please.

I'd also be interested to hear how the 4QD controller works out when jackrae buys one. Be careful of a controller that can put out more power than your motors can eat