the rating on any electronic device should be double the controlled device.
that would be for 75 volts the transistor should be rated for 150 volts
minimum. You should also use shunting diodes when switching an inductive load.
You also want to over rate the current. The other thing you need to do before
you buy the transistors is make sure that the switching voltage of the gate
matches the controller you will be using.
Yes you could use a low power controller. Cheap is good unless you need to
ramp up the current and the controller is not designed to do so. Just make
sure the controller can handle all functions you want to use.
Kevin
PS I use transistors here. that is not the case as we have already stated what
we are talking about. Transistors are current driven fets are voltage driven.
On Thursday, July 10, 2014 04:40:59 PM you wrote:
> Kevin, Really good information. You got me thinking. When you say MOSFETs
> are inexpensive, I took a look on Ebay an was able to buy STP75NF75 MOSFETS
> rated at 75 Volts and 80 Amps for less than one dollar each. So if I put
> say 5 of these on a large heat sink and parallel them it seems I could
> control 75 Volts and 400 Amps. Rather than opening and adding to an
> existing PWM controller, which could be messy and difficult. couldn't I
> just purchase an inexpensive low power PWM DC motor controller- say 20
> volts and 10 amps- and use that to drive the gates of the STP75NF75
> MOSFETs.
Thanks for the information.
> Art
Posted by: Kevin Pemberton <pembertonkevin@gmail.com>
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