Burned my speed controller... help

[topgun]

My alfa was out on the pond when it suddenly stopped right after I surfaced.

It lost complete power(the 8 amp fuse went) and the submarine was dead in the water. It eventually floated to shore and I thought that I had only
burned the fuse.

I removed the fuse and tried to just turn it on while on the stand. It started to smoke and I turned it off. The next time it stopped smoking and the motor did not run at all. The speed controller burned. So I bought this speed controller, installed it, and then the motor burned.

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXBJ60&P=7

What motor would work with my Alfa? What rpm's does the motor have to be around? I was thinking about this one...

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXDDA1&P=ML

Would I need a gearbox again?
Thanks,
Tom Kudla

[m. munger]

Tom]



Edited By M. Munger on

[color=#000000]Tom]



Edited By M. Munger on 1083636777

[topgun]

I am scale 1/96 and

I am scale 1/96 and have 4500 mha battery running at 7.2 volts. The propellor is 2.5 inches in diameter. What if I installed the car motor but limited the top speed by radio adjustments?

What RPMS should it run at approximatly?
Thanks,
Tom Kudla

[koeze]

I usually pick a motor

I usually pick a motor that is able to run at full throttle connected to the propshaft without reduction.
This usually means a motor that runs at 5000rpm or less.
A 2,5" prop requires quite a lot of torque to hurl around.
These car engines are able to consume very large amounts of power.

My advise would be to find yourself a normal marine use engine. The large temperatures that are created when running a motor like this may also create problems. The confined space in a submarine does not offer much possibilities to lose excess heat.

Look around this forum and you'll find many examples of how other drive their subs.

Good luck

EJK

[thordesign]

The Alfa works really well

The Alfa works really well with the Graupner 500E motor. She will draw around 5 amps full throttle and will really move out!

[JWLaRue]

Matt,

....is that with or without

[color=#000000]Matt,

....is that with or without a 3]

[thordesign]

Jeff,
With all of the surface

[color=#000000]Jeff,
With all of the surface area of the Alfa prop it definitely needs at least a 3]

[carcharadon]

Tom, I've run RC 10

Tom, I've run RC 10 cars at maybe 30-40 mph up and down my street. I've burnt out many ESCs. Too much heat is usually what destroys them.

[JWLaRue]

Hi Matt,

Thanks for the confirmation.

The

Hi Matt,

Thanks for the confirmation.

The reason that I raised the question was to help/try to point out that only talking about motors is generally not very useful unless other factors like prop size and gearing reduction are taken into account.

-Jeff

[topgun]

Matt, I think it was

Matt, I think it was my motor at fault, not your speed controller. The motor was dieng and as a result drawing more amps through the speed controller. As for the motor, you said you are running on the 580SE with gear reduction. Are you running it at 12 volts?

I have one more question about my battery hookup, I have three 1500 mh nicad batteries hooked up in series at 7.2 volts. I read somewhere that they will explode, is this true?

Thanks for the help,
Tom Kudla

[topgun]

**Error in my post before,

**Error in my post before, I ment 500E not 480SE

[Guest]

Tom,
If your batteries were really

Tom,
If your batteries were really hooked up in series, 21.6 Volts would fry most hobby ESC's. Did you mean in parallel?

[thordesign]

Hi Tom,

I use the Graupner

Hi Tom,

I use the Graupner 500E motor at 12 volts on a single 2000 mah nimh pack. She pull about 5 amps at full throttle. You can buy the motor/gearbox combination for about $40.00 from hobby lobby. She will have more speed than you will be able to control!

When you get a good combination, please let me know. Send your SC back to me and I will repair it for you at no charge.

I would not recommend connecting seperate battery packs as you describe. You can create some odd voltage differential faults.

[Guest]

Can't beat having a speed

Can't beat having a speed controller that is thermally protected- makes them virtually bombproof.

I like to use electric motors from heater blowers out of cars. Cooling fan motors work well too.

These motors suit larger models best- 4' and longer, but they push out a shed load of torque, generally rev between 3000-5000 RPM and will crank just about any model prop you can think of, direct drive.

The current draw is minimal, as their design is multipole and the large armature diameter means the motor does it's work easy.

They're cheap to buy too!

Any disadvantages? Hmmm , a couple-

Too big for small models.

They generally require at least 12 volts for good operation. Although I don't consider this a disadvantage.


Andy

[topgun]

I think im getting the

[color=#000000]I think im getting the graupner 480(would get 500 but I run on 7.2, should have gone 12 volts) with 4]