Need Wiring Help For 12 Volt Motor

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vtsteam:

--- Quote from: bertie_bassett on December 17, 2014, 06:13:26 PM ---vtsteam: your drawing with the joystick closed but relay de-energised is a bit confusing, but dosnt really effect much.
--- End quote ---

Well it's my mistake and it does actually show an impossible state, and is confusing when trying to trace what is happening, so I'm claiming it as a problem -- at least for me! :)

I believe the PWM version of the circuit (not the high speed version, which is fine) that I showed is just plain wrong as a direct result of mis-reading the circuit, based on my mistake in showing the switch closed and the relay opened. I might be able to re-draw it properly, but I need a mental break from it for a bit. I do like your diode version if it proves out.

--- Quote ---the biggest problem with PWM is that its basically just turning the motor on and off very fast, so if you were to feed a relay with it, it would be going on off on off on off which i doubt it would like at all.
--- End quote ---

Nah, I see the reduced effective voltage to the relay if the PWM is turned down as a problem. not the fact that it's pulsed DC. But that's moot. It's obviously better to feed it straight from a full voltage DC power supply in either case.

--- Quote --- hope that clears things up a bit.
--- End quote ---

They were clear already, so no problem. :beer:

velocette:
Lets edit my earlier explanation to make it clearer please see the PDF File I Posted on "This Works"

Snub in his original posting shows 2 Joysticks 2 Relays 1 Power Supply 12 volts DC 1 PWM speed control 1 12 volts DC motor

Attempting to use the Existing equipment as indicated for the starting base for this circuit.

The motor is always started on Low speed with the latching Joystick Fwd Off Rev.

A lot less load on start up than reversing a relay engaged at full speed.

Substitute the Push Button with the second Joystick with Momentary Contacts

Then use the contacts On the Second joystick to Give high speed by shorting the speed control Pot to High Speed

The High Speed is maintained as long as the Second Joystick is held Closed.

Eric

bertie_bassett:
whoops just noticed my diode was in the place :Doh:

heres an ammended drawing, iv also redone the 'confusing' relay situation, should be easier to read.

vtsteam:
Well, Berte, now all the relay contact designations and pin numbers PhilF clarified are wrong. Look out Snub! :zap:

(I said the joystick wiper needed to be moved to a different position),

Diode in wrong place.............this is getting to be funny! :lol:

I guess we'll muddle our way to something that makes sense.

Kinda like chimps typing up Shakespeare's Hamlet by hitting random keys -- eventually

bertie_bassett:
Ahh it will all work in sure, iv only put the relay contacts in an energised state. ( although technically thats the wrong way to draw a schematic). Shouldn't go bang.

I think we've moslty got it now, just need that diode or extra switch adding to the joystick.

In regards to that diode, it will need to be capable of handling the motor current ( plus a bit extra) as its feeding the power to the pwm modual. So a spec higher then 12V 3A should do the trick.

Its been far too long since I draw up proper drawings, but the knowlage is on there somewhere.

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