I have a series wound DC motor and am concerned about no load runaway. The motor has separate terminals for the field and armature. I was wondering if I can simply use separate current control of the field to help control the speed and limit no load runaway. I appreciate any help with this.
What motor are you using? I used magnets on my Prestolite MTC 4001 into a tachometer and rev controller. Most EV-ers use ADC 9" motor and forget to take vehicle out of first gear and put commutators in orbit. ME So I sent it off to Warfield electric and they re-engineered it and made it stronger with better and stronger buss bars that are tied down. You can use a centrifugal switch to break circuit too. So how big or what brand do you have?
Also field current in a series wound motor is same as armature and my field current was hundreds of amperes. Actually what ever a DCP-1200 can do.
powering the field independantly will prevent a runaway condition under power, but the source you are using to power it should at least be able to match your controller current output.
doing this means you will be able to get regen, by bypassing the controller.
*WARNING* don't use a dc-dc (even if its isolated) to inject additional current while the motor is still wired in series, as you will destroy the freewheel diodes in your controller.
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km