[Newbie] Help me decipher wiring diagram.

[xbartx]

That's how I'd do it. But I'd probably just use a single pole relay, unless you already have the dual.

I'm hoping to use the relays on my controller, I just need to find out if they have a suppression diode on the coil.

 

[Asm109]

Its a safety thing. What if the motor was lifting a load and power failed? Brake engages and nothing falls.

 

[RJSakowski]

I have a brake on the z axis of my Tormach mill. It's purpose is to prevent the head from going into free fall when the stepper drive isn't energized. The brake is active with no power applied and is disengaged when the stepper is powered up. This is a requirement when a ball screw is used as it can be back driven.

 

[mksj]

Diode and power 24VDC supply are to operate the brake relay/contactor, activation is by CN1, reverse diode is either separate or can be integrated into the relay. It prevents a reverse voltage spoke when the relay opens and spike can be around 130-150V which can damage a SS switch used by the controller. The relay or contactor uses a separate voltage supply depending on the brake used, this could be a motor brake, and can be significant current. Typically this is switched AC going to a diode bridge which operates a motor brake or can be various voltage and current types.

 

[xbartx]

I have a brake on the z axis of my Tormach mill. It's purpose is to prevent the head from going into free fall when the stepper drive isn't energized. The brake is active with no power applied and is disengaged when the stepper is powered up. This is a requirement when a ball screw is used as it can be back driven.

This is for a lathe spindle and being uneducated about servos, I assumed I needed a brake. The DC motor this is replacing needed one. I now know I don't need one with a servo.

 

[markba633csi]

Now I see the reasoning behind the dual pole relay- if a single pole were to stick closed that would be unsafe. Two poles gives two chances to break the circuit in a deadman system
How much safer? Hard to say without a statistical analysis and my math skills are lame as in duck
The brake coil probably should have a voltage suppressor device across it

 

[Chip Hacket]

Does this look right?

View attachment 510037

Looks good to me! Energizing the control relay activates the brake coil, releasing the physical brake. As others have mentioned, having two poles on the brake coil relay isn’t strictly necessary, but it’s fine if used. The diode is a flyback diode, which protects the drive’s electronics from voltage spikes generated when the magnetic field in the control relay coil collapses after de-energizing.