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-   -   twin motor starter boxes (https://www.rctech.net/forum/radio-electronics/313340-twin-motor-starter-boxes.html)

lowey79 07-20-2009 04:45 AM

twin motor starter boxes
 
Which would make more torque in a twin motor starter box?

1. The motors wired in series

2. The motors wired in parallel

JeromeK99 07-20-2009 11:02 AM

If you wire them in series you will have more voltage = torque. Wiring them in parallel will give them more capacity(mah) = more time.

Series = double the voltage
Parallel = double the mah

Most twin motor starter boxes I've ever used have two 6-cell 7.2v packs wired in series.

Jerome :tire::tire:

Dave H 07-20-2009 03:15 PM

If you mean motor wiring, not battery wiring, then it works the other way, parallel motor wiring will provide more power and torque at a given battery voltage. Each motor will see more voltage, and draw more current, thus more power. Of course the motors need to be able to handle the full battery voltage, and the batteries need to be able to deliver the current.

lowey79 07-20-2009 08:08 PM

Sorry, i should have made it clearer...

Dave H had the answer i was looking for!

Cheers!

JeromeK99 07-21-2009 12:24 AM


Originally Posted by Dave H (Post 6091945)
If you mean motor wiring, not battery wiring, then it works the other way, parallel motor wiring will provide more power and torque at a given battery voltage. Each motor will see more voltage, and draw more current, thus more power. Of course the motors need to be able to handle the full battery voltage, and the batteries need to be able to deliver the current.

Good catch Dave! He was pretty clear on saying motor.. never occurred to me because I've only ever seen twin motors wired together then to the power in series..

Hmm.. need to think on that one for awhile.. i still think you need your batteries setup in series for higher voltage. Given that they are, 2 motors in series would draw twice the amps through the circuit.. but why would they draw any less amps or pull more power if they are taxing the same power source from 2 separate curcuits?

I need to talk that over with my electrician buddy.

Very interesting none-the-less!

Jerome :tire::tire:

Dave H 07-21-2009 03:52 PM

Jerome, you are correct about the batteries, series batteries will provide more power than parallel batteries, again assuming everything is up to it.

Essentially series/parallel works in opposite directions, depending whether you are considering a power source (batts), or a load (motor).

Of course this is all just theory, I should point out that I don’t know didly about actual starter boxes, not sure if this is what you should do. Gearing needs to be considered when jumping around in configurations like this, just like we do with our cars gearing.

Hope this helps more than it confuses. Cheers!

gulio 07-22-2009 07:52 AM

The parallel motors will have more power (over twice?) and will have more speed (over twice?) if all else is equal.

Espeefan 07-22-2009 08:36 AM

To the best of my knowledge, all dual motor starter boxes come wired in parallel from the factory, don't they? I can't imagine trying to use a dual motor starter box, with the motors in series. You would get half the speed and half the cranking torque.

gulio 07-22-2009 08:47 AM

I'm not a nitro , and only have experience with one starter (handheld) I think the 2 packs were in series and the motor was only single (like parallel). I suppose you can configure it any way you like depending upon how much wheel rpm you want.

It should be pretty easy to get an increase or tork, or speed or both in a certain starter box. Is there potential for a market for repair/upgrade?

Dave H 07-22-2009 08:53 AM


Originally Posted by gulio (Post 6100598)
The parallel motors will have more power (over twice?) and will have more speed (over twice?) if all else is equal.

In theory the speed would double, the torque would also double, the power would increase by 4 times. (power is related to torque times speed)

In practice it’s a little less than that due to voltage sag in the battery, current driven voltage losses in the wiring and such, and assuming brushed motors brush/comm friction & bounce etc.

mgtmadness2007 07-23-2009 05:45 AM

How do you know if it is in series or paralell or whatever?

lowey79 07-23-2009 06:09 AM


Originally Posted by mgtmadness2007 (Post 6105375)
How do you know if it is in series or paralell or whatever?

OK, if the motors are wired in parallel, the positve wire will connect to the positive terminal on both motors and the negative wire to the negative terminal on both.

If they are wired in series, then the positive wire connects to the positive terminal on one motor only and the negative wire to the negative terminal on the OTHER motor. The two remaining terminals are then connected together to complete the curcuit.

lowey79 07-23-2009 06:23 AM

Well i re-wired my X5 starter box because it was a little lazy when trying to start my OS Speed... I went from series to parallel and WOW! What a difference... It now winds my speed over almost fast enough to engauge the clutch!

Oh, i should mention that the X5 runs 2 550 size motors and i'm using a 12v gel type battery

If anyone is having trouble starting their engines with a twin motor starter box, then i highly recommend that you try this mod to get a bit more out of the box :)

mgtmadness2007 07-23-2009 06:29 AM

Well I have the Mugen starter box for my RC8T, I have upgraded the wires, and upgraded to deans connectors. using 2 3300 Mi-MH stick packs, seems to lose power and torque quick also using 2 55 turn crawler motors. should i just upgrade the batteries to 1 lipo
?

Espeefan 07-23-2009 10:24 AM


Originally Posted by mgtmadness2007 (Post 6105491)
Well I have the Mugen starter box for my RC8T, I have upgraded the wires, and upgraded to deans connectors. using 2 3300 Mi-MH stick packs, seems to lose power and torque quick also using 2 55 turn crawler motors. should i just upgrade the batteries to 1 lipo
?

You are running two 55T crawler motors in your starter box? Just curious why? A 55 turn motor does not have more torque then a 21 turn motor. Torque is directly related to current draw. The more turns a motor has, the more resistance it has. The more resistance, the less current it will draw. The less current, the less wattage, and the less overall torque. You aren't doing yourself any favors by down grading [in fact] to a set of 55 turn motors.


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