3520b motor replacement.

[allen thunem]

I have a chance to pick up a new lesson 3hp 3ph motor for super cheap. My question is this will my vfd handle a 3hp motor and secondly
what is the frame number for the current motor that came on my lathe.
I checked the spec plate and product info page for powermatic as well as my owners manual
and found nothing with this information. can anyone help ?????
has anyone done an upgrade to more powerful motor??? if so what did were the motor specs?? frame number etc etc

[Reed Gray]

Not sure. I know with my Robust Beauty, it came with the option of 2 or 3 hp. Biggest problem could be how you mount it. If all the holes are the same, no problem. Not sure if your phase converter will work for both 2 and 3 hp or not.

robo hippy

[John K Jordan]

You can look up the specs for the exact VFD on your lathe in the Delta manual using the model number on the VFD. The manual, if you don't have one, can be downloaded. It will give the current capacity of that VFD. If the VFD on your lathe will not handle the larger motor you can always install a larger one one, but they are expensive.

I didn't check my 3520b, but I did discover that the 120v Jet 1642 is advertised at 1.5 HP which, according the VFD specs, is greater than what the VFD will supply. The motor is indeed 1.5 hp but the VFD will only drive 1 hp. I wonder Jet derated the motor to solve some problem or more likely, to save some money on the VFD.

JKJ

[Joe Kaufman]

The shaft of the lesson motor won't be long enough for a 3520B replacement.

[Jason Edwards]

The 3HP motor would run on the inverter, but as I understand it you would only get 2HP out of it, as that's all the inverter is rated for. To get a full 3HP you need to change both the motor and inverter. One fellow before said the shaft wouldn't be long enough either, so you need to check that out as well as the bolt hole arrangement as somebody else mentioned.

[Dennis Ford]

The motor that comes on 3520B is a custom design with a long shaft, no standard motor will match it.
+1 on the existing inverter being rated at 2 HP max.

[Doug Rasmussen]

The motor that comes on 3520B is a custom design with a long shaft, no standard motor will match it.
+1 on the existing inverter being rated at 2 HP max.


It's really irritating when machine builders use custom motors. The classic example is the old Delta Unisaws with the special motor mount.

When Powermatic came out with their Unisaw equivalent they used a "standard" mount style. With the old Unisaws it was possible to adapt a standard motor style to the saw, but it involved cutting the saw's cabinet for clearance to tilt the arbor.

[allen thunem]

well damn that just ruined my whole plan
thanks everyone for the info




The motor that comes on 3520B is a custom design with a long shaft, no standard motor will match it.
+1 on the existing inverter being rated at 2 HP max.

[Jim Underwood]

well damn that just ruined my whole plan
thanks everyone for the info

Yup. Ran into the same problem with the Jet 1642. I took the motor to a rebuilder to see if they could match something up. NO DICE.
By the way, it's the same basic motor and VFD as the Powermatic... Just a different shaft and mounting system.

[Bill Boehme]

I have a chance to pick up a new lesson 3hp 3ph motor for super cheap. My question is this will my vfd handle a 3hp motor and secondly
what is the frame number for the current motor that came on my lathe? ....

The inverter used on the Powermatic 3520 series used to be a Delta VFD015A21(A or B revision). Even though Delta EOL'ed the VFD-A series inverters some time ago Powermatic was able to continue putting them on new machines for quite a while afterwards. I suspect that they have switched to a current model by now, probably the VFD-B series. If so, the model number would be similar. Most likely it is a VFD015B21A. The "015" means 1.5 kW (2 HP). The "21" means it is designed for 230 VAC single phase input power. I could've find the manual for the obsolete A series inverters on the Delta site, but here is a link to the manual for the Delta B series inverters (http://www.deltaww.com/filecenter/Products/download/06/060101/Manual/DELTA_IA-MDS_VFD-B_UM_EN_20080725.pdf).

Normally, the frame size is required for the nameplate data, but when a motor is considered an integral part of the machine and is a modification to the standard frame size then the nameplate won't carry much more than the operating voltage and phase.

Sometimes an inverter can be used with a motor that is the next size up, but even when it can the operating restrictions as previously mentioned by Jason Edwards basically limit it to the performance of the rated power output.

While 3 HP sounds enticing, it is unlikely that any of us actually needs that much power unless we routinely stall the motor (2 HP in this case).

[allen thunem]

that is some good information bill. thank you




The inverter used on the Powermatic 3520 series used to be a Delta VFD015A21(A or B revision). Even though Delta EOL'ed the VFD-A series inverters some time ago Powermatic was able to continue putting them on new machines for quite a while afterwards. I suspect that they have switched to a current model by now, probably the VFD-B series. If so, the model number would be similar. Most likely it is a VFD015B21A. The "015" means 1.5 kW (2 HP). The "21" means it is designed for 230 VAC single phase input power. I could've find the manual for the obsolete A series inverters on the Delta site, but here is a link to the manual for the Delta B series inverters (http://www.deltaww.com/filecenter/Products/download/06/060101/Manual/DELTA_IA-MDS_VFD-B_UM_EN_20080725.pdf).

Normally, the frame size is required for the nameplate data, but when a motor is considered an integral part of the machine and is a modification to the standard frame size then the nameplate won't carry much more than the operating voltage and phase.

Sometimes an inverter can be used with a motor that is the next size up, but even when it can the operating restrictions as previously mentioned by Jason Edwards basically limit it to the performance of the rated power output.

While 3 HP sounds enticing, it is unlikely that any of us actually needs that much power unless we routinely stall the motor (2 HP in this case).

[Bill Boehme]

One other thought is that not just any old three phase motor is a good deal just because it is cheap. Motors rated for inverter duty have windings with higher strength insulaton that is able to withstand the high voltage spikes that are a characteristic of inverter operation.

Cooling is another issue because the motor will often be operated below its rated speed which means that the fan won't be providing sufficient air over the motor to keep it cool. Motors that are rated for inverter duty can operate over a wider temperature range.

The bearings in inverter rated motors have electrical shielding to prevent internal arcing from pitting the balls and raceway. Inverter duty motors may be rated for operation at speeds greater than the nameplate speed at 60 Hz

[Mike Peace]

that is some good information bill. thank you
I bought my 3520B in 2008 and the manual specs say the VFD is VFD015S21A. Wonder what the difference is between the B model VFD? I did find a link to download the S manual. http://www.delta.com.tw/product/em/drive/ac_motor/download/manual/VFD-S_manual_en.pdf

[Bill Boehme]

I bought my 3520B in 2008 and the manual specs say the VFD is VFD015S21A. Wonder what the difference is between the B model VFD? I did find a link to download the S manual. http://www.delta.com.tw/product/em/drive/ac_motor/download/manual/VFD-S_manual_en.pdf

You are right and I was confused about which inverter the lathe used. A few years ago I was trying to help someone find a replacement inverter and they said that the inverter that was on their lathe had been discontinued.I didn't bother verifying that, but they wound up going to Powermatic and buying the replacement from them.

The bottom line appears to be that the Powermatic currently uses and has always used the VFD-S series inverter. The VFD-S inverter is a basic no frills V/f inverter. The VFD-B series inverters have the ability to operate in sensorless vector and closed-loop vector modes.