building speed controller out of solenoids?

[jonny]

i was thinking about building a cheap bang-bang speed controller today and came across this:

http://www.ukrobotics.com/html/hints&ti ... ontrol.htm

has anyone tried this or have any wiring diagrams?

[daliad100]

You wire up the contacts of the solenoids in an h bridge and the coils of the 'diagonal' solenoids together and have a microswich to turn on each coil pair.

http://www.6x6world.com/forums/conte...ridge.jpg.html

Pretty similar to that but with two microswitches instead of a switch.

[jonny]

thanks

[craig_colliass]

This may be ok

http://cgi.ebay.co.uk/WINCH-SOLENOID-24 ... dZViewItem

[typhoon_driver]

I'd recommend using solid state relays instead of solenoids.

http://www.jaycarelectronics.co.uk/prod ... BCATID=754

These would happily do the job. Mount it to a metal chassis for heat dissipation and these will keep running all day long. Stalled a small mag for 5 seconds or so with one of them. The mag was nackered but the relay was fine.

[woody]

I'd suggest you weigh carefully the price of building a cheap bang-bang speed controller versus that of proper motor controller.

[jonny]

thanks for all the reply's i probably won't use bang-bang control. i was just thinking about using it temporarily until i can afford a proper one. but i'll just wait and hope someones able to sell me one used

[leorcc]

I'd recommend using solid state relays instead of solenoids.

http://www.jaycarelectronics.co.uk/prod ... BCATID=754

These would happily do the job. Mount it to a metal chassis for heat dissipation and these will keep running all day long. Stalled a small mag for 5 seconds or so with one of them. The mag was nackered but the relay was fine.

These only close one way, so using them in an bang bang system would short the connection to the battery. Unless you put a hefty diode in front of every SSR. They are very good though, we've used them in our spinners as well.

[woody]

SSR H Bridge
Take a R/C servo ... remove motor..... and replace with SSR H Bridge using the two spare wires on the left of pic.

This will/should give a crude fwd/rev speed control.
The negative MUST be common to both the R/C receiver /servo and the main battery... if your using a BEC it will be.
[attachment=0:2qo9qx0x]ssr h.JPG[/attachment:2qo9qx0x]

[craig_colliass]

The contactor I suggested is a motor controller in itself with forward / stop / reverse all there with two units and 2 servos with micro-switches you have a simple bang bang controller for 2 motors. but I would still recommend a PWM controller.