On 12/26/2015 05:17 PM, Ben Potter wrote: > I tend to use Amphenol connectors... > They are..._slightly_ pricey though - but very convenient if you have to > swap a motor out
I've heard this advice before but I've never fully understood it. All of the stepper motors I buy have bare leads, so I'd need to add a connector to the stepper motor and a mating connector to the motor cable. That's not too bad when building a machine, but the recommendation is specific to replacing the motor. If the motor ever needed to be replaced, I'd need to install another connector on the motor leads. I have several connectors in stock, and the pins and sockets and crimpers, but finding the correct connector components is always more trouble than desoldering the old motor and soldering a new motor. I guess the connector strategy works for people who buy an extra motor or two and install the connectors while building the machine and keep the spare motors with the machine so it's easy to plug in a new motor. Soldered connections are very unlikely to accidentally disconnect and take out a stepper motor driver. In some applications, I've been able to cut each motor lead an inch longer then the previous and do the same on the cable to make a long staggered series of soldered splices that are thin enough after the double layers of heat shrink to tuck into the T slot on extruded aluminum framing (80/20, etc). I press in a piece of black plastic T slot cover for a flush installation that hides the motor cable. You can't do that with a connector, other than probably four staggered pairs of insulated quick disconnects. If you're using coolant or have a lot of fine dust, you can get waterproof connectors (there are decent cheap ones on eBay), or you can epoxy coat the inside of the outer piece of heat shrink over soldered connections, and when you shrink it the epoxy oozes out the ends and makes a waterproof seal. Try to keep the epoxy away from the soldered connections or it'll be a real pain to replace a motor. My only caveat with soldered connections is that they must be protected from flexing and vibration. The solder wicks into the stranded conductor and creates a stress riser, and the wire can break at that point if flexed or shaken, but if you secure the cable to prevent it from flexing or vibrating you'll have a very reliable (and inexpensive) connection. I'd use connectors for things like a 4th axis or rotary table that you want to disconnect and remove when not in use. Obviously, you should power down before plugging or unplugging stepper motors. You might want to wire nut the motor connections during the test phase, to ensure that the phase wiring is correct so you don't have a random patchwork of fixes for that in the configuration file, which makes major upgrades of LinuxCNC take a bit longer to reconfigure. I like using the default configurations (or variants thereof with minimal changes) and wiring it so all axes move in the correct directions. That's particularly important if you have a CNC router with two X motors, with one on each side of the table, and they move in unison. Initially exercising the machine with wire nuts and extra long motor cables is also a good way to avoid wiring an axis only to have some motion rip out the motor wiring. It's surprisingly easy to zoom in on the wiring details and lose sight of the big picture of what moves where and how the cable must be routed to allow the full range of motion. You can temporarily cable tie the excess cable and move over the full range of motion BEFORE cutting a motor cable an inch too short. Some people use the XLR audio cable connectors. The Chinese versions are cheap. They look a bit cheap, but they seem to work well for wiring stepper motors. They produce reliable and relatively high current connections. ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
