R2E3 4 wires in servos

[ccoleman]

Hi all,
I just found that the servos on my R2E3 have 4 wires. There are the 2 black and red heavier gauge wires that you'd expect, but then there are 2, maybe 18 gauge, black and red wires that are connected to a series of, what look like brushes, behind the bei encoder housing.

What are those extra wires and should I hook them up?
Thanks,
Chris

[machintek]

Velocity Feedback loop (tach) is what they are.

George

[Al_The_Man]

What drive are you hooking them up to, if using current drives in torque mode you do not need the tach, I usually take the brushes out also.
Al.

[ccoleman]

Ah, thank you.

I'm going to use the Dugong's on x, y and a 302v on the z. If I can take out those brushes it ought to make it a little easier to mount the new encoders.

Thanks,
Chris