Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
Are we talking beetleweight, or something bigger? The controllers under 20A are not all that expensive. personally, I would go with one bigger moter & ESC - half as much work to mount it. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Fri Mar 02, 2007 7:26 pm
dyrodium Experienced Roboteer
Joined: 24 Aug 2004
Posts: 6476
Location: Sydney
Featherweight...
I'm too unsure on it to really talk about it much, but might well be using a brushless motor. I had a thought I could use just one and run the other side on a castor wheel, that might work a bit better. _________________ ( •_•)
Okay, I'm pitching some ideas around at the moment. I'm having a glance at brushless. I'm looking for a motor between 1Kw and 1.2Kw, between 5000 and 8000rpm @ 18v. I don't need high RPM, I just need torque. The biggest problem I see is controllers. I'm wondering what some of the electronics guru's think about this, but how hard is it to build a simple ON/OFF sensor'd brushless controller with REV?
How feasible would a PIC running 3 small half-bridge fet drivers to power 12 x IRF1407 fets with a bit of ADC feedback for positioning??
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
I think you are looking for a motor that doesn't exist and if it did, it would be a special, expensive industrial item. Use off the shelf parts and go for a high efficiency brushed motor that reverses easily. Sounds like you are building an electric flipper to me... _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Thu Jun 07, 2007 9:21 pm
Knightrous Site Admin
Joined: 15 Jun 2004
Posts: 8511
Location: NSW
Torcman seem to be the only guys that make decent brushless motors within this spec.
They are just pricey and I was hoping someone else would have an alternate to them.
I've currently got a 14.4v Dewalt motor (400watt according to Dewalt) @ 18v designed for it, but can see it being under powered. _________________ https://www.halfdonethings.com/
Thu Jun 07, 2007 9:32 pm
Nick Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
The Torcman motors are just biggr than other outrunners, they are still relatively low torque at startup, for the reasons Jake posted about. For the money, I would get a short Mag and save weight in some other part of the bot with titanium - same overall price for the bot and likely a better balance of weapon vs armour. The controller will be WAY cheaper & easier for the Mag as well. _________________ Australian 2015 Featherweight champion
UK 2016 Gladiator champion
Thu Jun 07, 2007 10:07 pm
Fish_in_a_Barrel
Joined: 30 Sep 2006
Posts: 673
Location: Perth, Western Australia
If you want to play with brushless controllers, grab yourself an F&P washing machine motor, wire it for 24V, and have fun.
you could probably do it with a standard pic if you used some "glue".
basically AND the outputs of your drive signal with a PWM out.
Alternately do what i am doing and use a 18F4553 (i think) with 4x PWM outputs in the one chip (4 *pairs* that is with adjustable deadtime). _________________ Mechanical engineers build weapons, civil engineers build targets
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