Hi I need help again please I have 24v / 100 va supply coming from a transformer to power a small motor. I need to be able to vary the speed from full power to 0 I know I will need a potentiometer but I am unsure of the size to use or if any thing else needs to be used as well as this.
Nick
This is my first project motor amperes is not marked on it but I know its will run at 24v as I have ran it on a 24v 1.5amp supply ,is there a way I can work out the ampage of it.
100VA at 24v than the transformer wil suply roughly 4 amps
if you ran it already on a 1.5 amp suply than i don't see anny problems
the easyst way to find out how much amps it consumed is measure it with a amp meter
I will post a schematic but that's a little later this day (have to work also and it's a busy day for me today)
if anybody have sugestions to improve it feel free
the assumption is that you feed it with a AC voltage if you have already DC voltage you can skip the 2 diodes in the power line
the advantige of of a PWM is that you use less energy on lower speeds
and you have a beter torque (stronger and more resposive) on lower rpm
if you use only a potentiometer (like you sugested in your first mail) you will burn a lot of energy in the potentiometer which required a big wattage potentiometer (= expensive and hard to get)
I am not familiar with that mosfet and it's one I can't buy overhere
keep in mind that they sell the mosfets amperage as it is measured by a single puls at a certain frequency and certain duty cycle at a certain D/S voltage
in real life they handle a lot less because its a repetitive puls with a variable duty cycle and higher voltages where you working with
also the cooling factor is importand (have a look into this mater verry intresting)
the easyst thing to do in order to handle more amps is to put 1 or 2 parralel
don't do to many (your driver will not be able to steer them anny more deu to an increasing gate capacitance)
hey guyz why are u confusing nickk1. he just want to control speed of a simple 24v DC motor.
As far as PWM is concerned it is a real good suggestion if he understands.
Good Luck Nickk1
For motor ampere if u know the exact voltage u can calculate its coil resistance and get the rough amps idea.