Hi all,
Got a customer who's asked me to look at a new machine they've gotten in which they're having trouble starting. It's a brand new machine, essentially a grinder with one motor driving three sets of grinding wheels via a hideously complex series of belts and pulleys. The motor is probably (at a guess) around the 30-40kW mark. Essentially, what they're saying is that they have to manually back the top grinding rollers off, start up the machine and run it for a few minutes, then they can stop it, wind the rollers back in, and it'll run fine. All of this screams "mechanical problem" to me, but they've asked me to take a look.
One thing they mentioned is that the main drive has a star-delta starter in it. For a brand new machine, this seems odd - surely a soft starter is about as cheap as all the control gear required for a S/D starter these days, not to mention the enormously reduced complexity. Just wondered if there's any practical reason a star-delta started might be more suited to this application than a soft starter? I suspect it's purely a case of "we've been building them this way for 20 years, if it ain't broke don't fix it", which is backed up by "our other plant has an identical machine and it has no such issues" - I believe the other plant is much older than this one, so it's likely just that the design hasn't been updated in 20 years.
If I were to suggest installing a soft starter, what might I need to watch out for?
Got a customer who's asked me to look at a new machine they've gotten in which they're having trouble starting. It's a brand new machine, essentially a grinder with one motor driving three sets of grinding wheels via a hideously complex series of belts and pulleys. The motor is probably (at a guess) around the 30-40kW mark. Essentially, what they're saying is that they have to manually back the top grinding rollers off, start up the machine and run it for a few minutes, then they can stop it, wind the rollers back in, and it'll run fine. All of this screams "mechanical problem" to me, but they've asked me to take a look.
One thing they mentioned is that the main drive has a star-delta starter in it. For a brand new machine, this seems odd - surely a soft starter is about as cheap as all the control gear required for a S/D starter these days, not to mention the enormously reduced complexity. Just wondered if there's any practical reason a star-delta started might be more suited to this application than a soft starter? I suspect it's purely a case of "we've been building them this way for 20 years, if it ain't broke don't fix it", which is backed up by "our other plant has an identical machine and it has no such issues" - I believe the other plant is much older than this one, so it's likely just that the design hasn't been updated in 20 years.
If I were to suggest installing a soft starter, what might I need to watch out for?