motors/wheels

**plargen** · 1st March 2013, 18:29

ok ive got a couple of the 24v reliance motors, which i got from Roger Plant a while back

i was thinking of using them to run a 4wd system using 8 wheels in pairs (maybe 12 in sets of 3) with a 3-1 , 4 -1 or 5-1 reduction

3-1 should give 14mph ish
4-1 11mph ish
5-1 9mph ish

does anyone think it will be a powerful enough drive for a heavy weight

hopfully if its ok then i should be able to make the robot quite small and compact which means i can put the weight in to the armour and weapons might go for weapons pods and make a few

**Bacon Wizard** · 3rd May 2013, 18:53

any power info? I don't have those motors, but also interested in what constitutes a decent HW motor. I'm guessing from a different thread I was reading yesterday that 5-6kw total would get you into the "serious power" category, which I suspect you need with 8-12 wheel drive.

Does anyone use starter-motors? That would be my natural inclination at around 2kw each, but nobody has mentioned them that I can see, so I'm assuming there's a downside.

**typhoon_driver** · 3rd May 2013, 19:02

starter motors draw too much current to be of any use

**Bacon Wizard** · 3rd May 2013, 19:12

Originally Posted by typhoon_driver

starter motors draw too much current to be of any use

Ah, hence you can't stick your car in-gear and turn on the ignition for more than a few seconds.

Tah (again!)

**blazerbotics** · 3rd May 2013, 19:27

and starter motors aren't designed to go in reverse. Only one I know of that run starter motors was Sumpthing that had 2 per side, one for each direction if I remember correctly.

Theres no point in going 6-8 wheel drive unless your running LEMs or Eteks. Having that many wheels will be very inefficient and I don't see what your going to gain.

**plargen** · 3rd May 2013, 20:07

dreadnought and a few other early robots used starter motors

and i was only thinking of using 8 wheels in a 4wd config 2 stuck together as their thin

**maddox10** · 3rd May 2013, 21:23

Project One used a Ford Fiesta starter motor @24V, completely rebuild for reverse -done with an Albricht SW88 24V B and a Sevcon SL1 speedo. That motor went into Scarab as pump motor.

Team RCC with Blackdevil Warzone had a machine with 3 startermotors in it. 2 for drive, 1 for the weapon, and those 3 together drained a 12V 45 Ah SLA completely in a fight.

The main problem with series wound motors is that they are very inefficient especialy compared to the modern PMDC motors.
If you're very lucky, you have an efficiency of 60%, when a Bosch 750 does 75% easely.

**mightymouse** · 4th May 2013, 07:03

Reliance motors - they are rare as rocking horse droppings and building a machine around them will put you in the same position as Meggamouse, damage one and you will struggle to get spares.

Starter motors - The first Velocirippa ran 1 starter motor, to reverse it you need to take a feed from the outer coils and reverse the direction of flow, extremely powerful but draws in excess of 400amps. Was faster with one motor at 12v than 2 littons on 36v. 5 minutes would drain a 24 AH battery completely flat, and one fight actually burnt all the insulation off the wiring leaving bare copper wires. You also need some serious DC contactors.

If you decide to sell the reliance motors contact me.......

Trevor