> From: Bruce Layne [mailto:[email protected]] > 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. I think it really comes down to 'how much will this downtime cost me'. And that really depends on what the machine is being used for - I _assume_ that the OP is building a hobby class machine, but I have seen nema17 steppers used on industrial metrology gear. This approach for me comes from running and maintaining industrial tools - where the reasoning is sound (it's not much more trouble for the manufacturer to wire up 7500 motors instead of 7000 and keep the extra as spares for when a customer's motor breaks). Spare drives (with quick disconnects), cables, and motors (with connectors) are then kept in stock and sold at usurious rates. On my own machines I keep the more predictable spares (including prewired motors with encoder) ready to swap out. As I've moved to heavier machines and industrial servos I've found that the motors generally come with connectors pre-installed. My router (using nema23 steppers) does have soldered in motors. If it's a hobby machine, or one machine amongst many - then the cost of downtime is probably less than the cost of keeping the spares. On an industrial tool 24 hours of downtime is likely to far exceed the cost of basic spares. As an aside - some manufacturers (igus spring to mind) do put connectors directly on their stepper motors. > 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. Good advice. It can be a frustrating fault to diagnose - particularly if the connection is intermittent and the blasted motor moves _most_ of the time. > 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. I have to admit I'm curious how industrial 4th axes are set up - I presume an extended ground pin at a minimum - or do they need a full power down of the machine too? ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
