Electronics expert needed

[walnutjerry]

After 20 years my Powermatic 3520A has developed a problem. The motor does not always start up and continue running------sometimes it will start and run for maybe a minute or two then kick off. Sometimes I unplug it wait a few seconds until I hear a click and plug it back up and it starts. Sometimes I have to go through unplugging restart several times before it starts up and runs. I had this issue once before years ago about 2003 and called Powermatic where they told me to check the wires. Well, I am not an electrician to say the least. There is an electrical schematic in the manual and a trouble shooting chart but I do not see much on the inverter.

So--------------do we have a member with the expertise to check this out and show me what and how to check it out if it occurs again in the future? Not asking for a freebie but I do not know where to find a qualified person for the job. Any help/advice will be appreciated.

Thanks in advance, Jerry

 

[bob vaughan]

Is the VFD you have?

 

[Oka]

No Expert, but it sounds like one of the legs on the 3 phase is cutting out possibly (being converted from single phase 220 power). You need to track it down.

The 1st thing I would check is the motor and its windings. This video will help you see how to do it. Checking Motor

If the motor is good, then check continuity from the VFD to the motor. If that is good, the you need to trouble shoot VFD. My 1st guess would be one phases is faulting. There are other issues to check if that is not the case. Here is a site that aims you in the right direction.
VFD Check

Good luck

 

[gmakra]

Three phase motors dont have a start switch nor do they have capacitors.it runs intermittently and sounds like the wires contain the smoke. If you dont know what i am talking about look up George Lucas electronics. Its fun reading.

i would start by looking at the VFD and seeing one are all the terminals tight? See if its throwing any codes. And verify the settings against the manual.

VFDs are no longer servicable so you may need a new one.

 

[walnutjerry]

No Expert, but it sounds like one of the legs on the 3 phase is cutting out possibly (being converted from single phase 220 power). You need to track it down.

The 1st thing I would check is the motor and its windings. This video will help you see how to do it. Checking Motor

If the motor is good, then check continuity from the VFD to the motor. If that is good, the you need to trouble shoot VFD. My 1st guess would be one phases is faulting. There are other issues to check if that is not the case. Here is a site that aims you in the right direction.
VFD Check

Good luck

 

[walnutjerry]

Three phase motors dont have a start switch nor do they have capacitors.it runs intermittently and sounds like the wires contain the smoke. If you dont know what i am talking about look up George Lucas electronics. Its fun reading.

i would start by looking at the VFD and seeing one are all the terminals tight? See if its throwing any codes. And verify the settings against the manual.

VFDs are no longer servicable so you may need a new one.

What do you mean by "throwing any codes" ?

 

[bob vaughan]

Look at the label on your motor to see if it is a three phase motor. The wiring diagram on the label will show nine wires instead of six if it is a tree phase motor. The VFD should be mounted on the back of the headstock.

Most 3520s had three phase motors that were controlled by a VFD box. The VFD box was most often fed 220 volt single phase current. The VFD box changes 220 single phase in to DC, then messes with it, then sends the current out as three phase to the three phase motor.

 

[Oka]

What do you mean by "throwing any codes" ?

This unit can come either with 220 or 3 phase. The OP needs to verify this 1st before proceeding.

 

[Charles Lent]

Jerry,

I'm a retired Automation Engineer (EE) and live in Kannapolis. We met once when Rob Hooper's wife was selling off his shop items.
PM me your phone number and address and I'll have a look at it for you.

Charley

 

[iclark]

A "click" sometimes indicates a thermal overload relay clicking back in when it cools.

With the lathe unplugged, check for sawdust buildup in the on/off switch, in the VFD, and in the thermal radiator fins of the VFD.

It is not always that simple, but sometimes one gets lucky.

 

[walnutjerry]

Jerry,

I'm a retired Automation Engineer (EE) and live in Kannapolis. We met once when Rob Hooper's wife was selling off his shop items.
PM me your phone number and address and I'll have a look at it for you.

Charley

PM sent Charlie

 

[Strom]

A friend fooled around with hers for a year. Talked to Powermatic till they were on a first name basis. I checked the VFD to no avail.
she ended up with a new VFD and smooth sailing so far. Similar set of symptoms to yours but mainly a speed issue.

 

[walnutjerry]

Look at the label on your motor to see if it is a three phase motor. The wiring diagram on the label will show nine wires instead of six if it is a tree phase motor. The VFD should be mounted on the back of the headstock.

Most 3520s had three phase motors that were controlled by a VFD box. The VFD box was most often fed 220 volt single phase current. The VFD box changes 220 single phase in to DC, then messes with it, then sends the current out as three phase to the three phase motor.

I looked at the motor label this am-----------it is a 3 phase motor. I operate it on 220 single phase current.

 

[walnutjerry]

A "click" sometimes indicates a thermal overload relay clicking back in when it cools.

With the lathe unplugged, check for sawdust buildup in the on/off switch, in the VFD, and in the thermal radiator fins of the VFD.

It is not always that simple, but sometimes one gets lucky.

I removed the switch from the housing this am, blew it off , pressed all the terminals to make sure all were snug reinstalled the switch. Voila!! It is running now without kicking out.

 

[walnutjerry]

Is the VFD you have?
View attachment 207157

It looks similar except mine is gold in color. model # of mine is VFD 015B21A

 

[bob vaughan]

What brand is it? The one in my photo is a Delta brand. Earlier 3520 VFDs were Baldor brand. I know where there's a manual for those that you can download.

 

[walnutjerry]

What brand is it? The one in my photo is a Delta brand. Earlier 3520 VFDs were Baldor brand. I know where there's a manual for those that you can download.

Bob, Thanks a bunch for the input on my lathe issue. I did not have to contact your friend. My son stopped by today and he got it figured out. He opened up the inverter and blew the dust out and then found a couple wires that were not tight in their terminal on the switch and tightened them. The lathe is running like new now.

Regards, Jerry

 

[Charles Lent]

I don't think Bob got this PM. Try again.

Charley

 

[bob vaughan]

Electronics! You just never know for sure until things are working again.
The loose wire business can create all kinds of distracting symptoms. The stories I could tell...
Well, my favorite story is a Powermatic service call. Drove two hours to get there. Couldn't understand what was wrong with the table saw from the symptoms. Finally looked carefully at the connections on the starter after checking tightness. One wire had been inserted too far and the screw was clamping down mostly on the insulation rather than the copper wire.

 

[walnutjerry]

Electronics! You just never know for sure until things are working again.
The loose wire business can create all kinds of distracting symptoms. The stories I could tell...
Well, my favorite story is a Powermatic service call. Drove two hours to get there. Couldn't understand what was wrong with the table saw from the symptoms. Finally looked carefully at the connections on the starter after checking tightness. One wire had been inserted too far and the screw was clamping down mostly on the insulation rather than the copper wire.

I just thought we had it fixed Bob. Went back to the shop after my son left and had issues with it kicking out again. Took 3 times resetting to get it to run long enough to sand 1 bowl with intermittent stops to blow dust off the bowl. Sanded several more bowls without issue-------------grrrrrrrrrrrrrrrrrrrr! We will solve the problem eventually.

Jerry