Driving a stepper motor with 24v brake, Wemos D1 Mini

I have 3 stepper motors with 24v magnetic brakes which uses 2 pair of wires for on/off state of the brake, additional to the 4pin input to the motor.

I have the wiring solved for the stepper motor, now I need to connect and control the magnetic brakes. I was thinking on using some 24v relays, the thing is, will the Wemos D1 Mini provide sufficient current to turn on a solid state relay? is it the right path to follow?

I was thinking on getting one of these 4 channel solid state relays that seems to work between 3.3-5v input on CH channels and provide an external 24v through the DC+/- to turn on/off the brakes.

Hi, Is the brake an AC or DC current? Check your SSR for AC or DC switching, there is a difference.

Tom... :)

TomGeorge: Hi, Is the brake an AC or DC current? Check your SSR for AC or DC switching, there is a difference.

Tom... :)

By the color of the wires, the break looks like it's AC, but's actually DC. Same as the Relay. Unless I'm missing something

TomGeorge: Hi, Is the brake an AC or DC current? Check your SSR for AC or DC switching, there is a difference.

Tom... :)

Brakes are always DC current as they are large solenoids with too much iron mass to respond to mains frequencies without massive losses. Just like magnetic door locks in fact. Also if the magnetic field reversed the brake would release 100 or 120 times a second!

You only need a logic-level MOSFET and a freewheel diode across the brake coil.

Can you please discuss for us why you want a magnetic brake and exactly how you intend to use it.

I ask because the brake will be very slow to engage and to release compared to the processing speed of the Arduino. Also investigate how heating effects the operation if you intend to use it continuously.

Paul

jtomasrl: I have 3 stepper motors with 24v magnetic brakes which uses 2 pair of wires for on/off state of the brake, additional to the 4pin input to the motor.

I have the wiring solved for the stepper motor, now I need to connect and control the magnetic brakes. I was thinking on using some 24v relays, the thing is, will the Wemos D1 Mini provide sufficient current to turn on a solid state relay? is it the right path to follow?

Did you get this solved?

I was thinking of using some 24v electromagnetic brakes to hold my z-axis in place (it's belt driven), since I have them on hand.

I'm somewhat confused on how to wire it so that it has the 24v supplied to the brake while the motor is on so the brake disengages.

This is my first build, and I'm using all salvaged pieces. It's going very well so far, but I'm not sure if the z axis NEEDS to be held by a brake so it doesn't drop, or if I can just return the spindle to a "home" type location, and zero it as part of the program. I understand it would need to be a part of every program, but that's ok for now.

Is the brake AC or DC? How much current does the brake require? Is your Z axis motor a stepper motor?

The brake is DC, 24v, 8w, and yes, the z axis is 2 steppers in series- one on left and one on the right.

Normally steppers will hold their position strongly as long as power is applied, even at standstill, have you tried turning power off and forcing the Z axis down by hand to see how much force is required to move it? Your 24V brakes are only 8 Watts so current will only be about 333mA, so those SSRs should work. As @Paul_KD7HB said, the brakes will be slow to operate, so make sure you delay long enough for it to release fully before moving motor or you might miss steps, same thing with stopping, delay long enough for brake to fully engage before disabling motor.
I cant say if the Wemos can output enough current to reliably trigger the SSRs, you may have to use helper transistors.

TomGeorge: Hi, Is the brake an AC or DC current? Check your SSR for AC or DC switching, there is a difference.

Tom... :)

These brakes are DC only, they are used in wheel chairs and scooters. They are extremely inductive and require free-wheel diode.