I am working on my very fist CNC conversion. I will be converting a Precision Matthews PM-833TV mill to CNC. Bench testing has been completed!!
The components I will be using are:
-Acorn board
-Three closed loops stepper drivers (Stepper Online CL86Y) - powered with a 70V/35V Toroidal transformer (AC)
- One 1700 Ounce closed loop stepper (Z-Axis)
- Two 1200 Ounce closed loop steppers (X,Y-Axis)
- Proximity sensors to establish home position.
- Two additional din rail mounted axillary transformers
- Heavy Metal double ball nut conversion kit.
- VFD to control spindle.
The steppers & drivers were purchased from Stepperonline. They are inexpensive but I think they will be suitable for a hobbyist home shop. These steppers came with cables. I was surprised to find that the encoder cables have a shield, but no drain wire. The motor wires are not even shielded. My run lengths for the X,Y axis should be under 6 feet. The Z-axis may be a bit longer. I am concerned that I could pickup EMI from the VFD. The folks at Stepperonline insist that they sell large numbers of these without issue. I like to do things correctly the first time. Do you think I should toss these cables.. or am I thinking too much?
Thanks... Richard
CLOSED LOOP STEPPERS - NO DRAIN WIRE
Moderator: cnckeith
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Re: CLOSED LOOP STEPPERS - NO DRAIN WIRE
Why not try what you have? Shielded wires help reduce noise but proper layout is just as important. I sometimes use shielded wires and sometimes use unshielded wires. My ClearPath servos (with step rates set to 400,000 steps per second) are not shielded. They work fine. I don't have a VFD in that system, but I hooked one up an AutomationDirect 120VAC VFD and 3/4-HP 3-phase motor about a year ago to see what would happen. It worked fine on the test bench.
-Mike Richards
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Re: CLOSED LOOP STEPPERS - NO DRAIN WIRE
It's not uncommon to find stepper motor power wires that are not shielded and the encoder shield could be grounded inside the connector to the signal ground connection. I would use what you have until you prove them to be too noisy. Met bet is they will work just fine. As noted by Richards in the last post, cable routing is also very important to help reduce noise in your system.
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Re: CLOSED LOOP STEPPERS - NO DRAIN WIRE
Thanks for all your thoughts. While I understand the theory here, I have virtually hands-on experience. All the best... Richard