Swapping 7.5 HP 3 ph. for 5HP single phase - Woodworking Talk - Woodworkers Forum
 12Likes
Reply
 
Thread Tools Display Modes
post #1 of 28 Old 10-22-2018, 03:09 AM Thread Starter
Junior Member
 
niedermee's Avatar
 
Join Date: May 2017
Posts: 9
View niedermee's Photo Album My Photos
Swapping 7.5 HP 3 ph. for 5HP single phase

My SawStop table saw currently has its original 7.5 HP, 220v. 3 phase motor, but the shop I'm moving into doesn't have 3 phase power - and it's not going to get it any time soon. There is a 5 HP Unisaw powered by 110v single phase motor currently set up in the shop. Is it possible to put the 5 HP in my SawStop? If so, what would be involved?
niedermee is offline  
Sponsored Links
Advertisement
 
post #2 of 28 Old 10-22-2018, 06:52 AM
Senior Member
 
Join Date: Jul 2008
Location: Florida Panhandle
Posts: 11,800
View GeorgeC's Photo Album My Photos
I do not know anything about the specific motor in your new shop, but I would question a 5 hp, 110 volt motor.


Is this a commercial shop? Your own place? or what?


George
Tool Agnostic and NoThankyou like this.
GeorgeC is offline  
post #3 of 28 Old 10-22-2018, 06:58 AM
Senior Member
 
ducbsa's Avatar
 
Join Date: Jul 2014
Location: Virginia
Posts: 357
View ducbsa's Photo Album My Photos
ducbsa is offline  
Sponsored Links
Advertisement
 
post #4 of 28 Old 10-22-2018, 08:03 AM
Senior Member
 
Join Date: Sep 2011
Posts: 25,991
View Steve Neul's Photo Album My Photos
That would get complicated on a sawstop. Part of what makes the breaking mechanism works is cutting off power to the motor. In your case that mechanism is made to operate on three phase. It may be you would have to change the braking mechanism to single phase. I think you need to contact technical support at sawstop to get better answers.
Steve Neul is offline  
post #5 of 28 Old 10-22-2018, 08:42 AM
where's my table saw?
 
woodnthings's Avatar
 
Join Date: Jan 2009
Location: SE, Michigan
Posts: 25,870
View woodnthings's Photo Album My Photos
Whats the amperage?

A 5 Hp motor draws 46 AMPs on 120 volts single phase, so you better have good supply wiring and breaker:
http://hvacwebtech.com/motoramps.htm

Other than that, if it fits up and the brake would work, why not?

The phase converter seems like the best approach and leave the Unisaw as is!
shoot summ likes this.

The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)

Last edited by woodnthings; 10-22-2018 at 08:50 AM.
woodnthings is online now  
post #6 of 28 Old 10-22-2018, 12:14 PM
Senior Member
 
Catpower's Avatar
 
Join Date: Jan 2016
Location: Frognot Texas
Posts: 2,197
View Catpower's Photo Album My Photos
I would bet a huge sum of money the Unisaw is 230 volt, I think the largest 115V induction motor made is 2 Hp
woodnthings likes this.

There is no app for experience
Catpower is offline  
post #7 of 28 Old 10-22-2018, 03:29 PM
Senior Member
 
Catpower's Avatar
 
Join Date: Jan 2016
Location: Frognot Texas
Posts: 2,197
View Catpower's Photo Album My Photos
If you do use the VFD I would make sure the braking system is hooked to L1&L2, when they create the third leg, under different loads it can vary the voltage, and that could cause the braking system to not function properly

There is no app for experience
Catpower is offline  
post #8 of 28 Old 10-22-2018, 08:02 PM
Village Idiot
 
epicfail48's Avatar
 
Join Date: Mar 2014
Location: Springfield MO
Posts: 4,685
View epicfail48's Photo Album My Photos
Provided that the motor frame and shaft are the same on the replacement as they are on the original, i cant see any reason it wouldnt work. To my knowledge, the sawstop system doesnt do anything with the motor other than cutting power to it, the actual stopping force is provided by slamming a hunk of aluminium into the blade. That said though, a VFD would probably be the better option, provided you can find one that can push enough power for a 7.5hp motor without breaking the bank. A rotary phase converter might be better for price, couldnt say though, havent done that level of searching on it

I need cheaper hobby
etsy.com/shop/projectepicfail
epicfail48 is online now  
post #9 of 28 Old 10-23-2018, 03:59 PM
Senior Member
 
Catpower's Avatar
 
Join Date: Jan 2016
Location: Frognot Texas
Posts: 2,197
View Catpower's Photo Album My Photos
I wouldn't try a rotary the VFD will provide a much better third leg. On rotaries you almost need a 3 channel O scope so you can add capacitance so the 3rd phase will be the right voltage. That being said I have used a shop made rotary converter on my Axleson lathe for about 22 years and no major problems, but since there are electronics involved it could be a problem


The VFDs have really come down in price, I worked at the BEP in Ft Worth, and they used all the first generation VFDs, a 7.5 hp unit was the size of a refrigerator and cost about $20,000, and were very parts and labor intense to keep them running



In this shop I have a Phase Perfect digital converter, it puts out perfect 3 ph, cleaner then the utility co provides, but it cost about $12000

There is no app for experience
Catpower is offline  
post #10 of 28 Old 10-24-2018, 07:57 AM
Senior Member
 
Join Date: Jan 2010
Location: NW Pa
Posts: 2,886
View TimPa's Photo Album My Photos
we have run a sawstop ics on a rotary converter with no issues. and I see no reason it won't run on a vfd.
TimPa is offline  
post #11 of 28 Old 10-24-2018, 10:40 AM Thread Starter
Junior Member
 
niedermee's Avatar
 
Join Date: May 2017
Posts: 9
View niedermee's Photo Album My Photos
Thanks for the replies. It's TRUE, I was mistaken, it is have 220. Swapping motors makes it much less expensive to get my saw up and running in the shop. We will eventually get another motor for the unisaw, as it would be great to have a dedicated dado saw set-up too.

Anyone else have dual table saw set-ups?
Catpower likes this.
niedermee is offline  
post #12 of 28 Old 10-24-2018, 10:53 AM
where's my table saw?
 
woodnthings's Avatar
 
Join Date: Jan 2009
Location: SE, Michigan
Posts: 25,870
View woodnthings's Photo Album My Photos
I have a triple saw setup ....

Quote:
Originally Posted by niedermee View Post
Thanks for the replies. It's TRUE, I was mistaken, it is have 220. Swapping motors makes it much less expensive to get my saw up and running in the shop. We will eventually get another motor for the unisaw, as it would be great to have a dedicated dado saw set-up too.

Anyone else have dual table saw set-ups?
My 3 saws are ganged together, not stand alone however. It makes for virtually zero blade changes, which I find to be a real pain, especially dado sets. I also have a stand alone 10" Craftsman Pro, with a removable riving knife, for unusual cuts where the splitter blade would prohibit them on the ganged saws. This is NOT a commercial shop , so these saws won't be heavy duty. The added space on either side of the blade on the center saw makes for great panel work. The left saws I use for ripping so, not need fpr space on the left side on that one. Since this photo, I have made a outfeed support table that is the same width as the saws, and is connected directly off the rear with a bridge which has all the miter slots built in.






The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)

Last edited by woodnthings; 10-24-2018 at 10:58 AM.
woodnthings is online now  
post #13 of 28 Old 10-27-2018, 12:12 AM
Ancient Termite
 
Join Date: Mar 2018
Location: Huntington Beach, California
Posts: 503
View NoThankyou's Photo Album My Photos
Based upon the schematics that came with my Grizzly Band Saw and I can't envision any manufacturer doing it differently.

The power switch contactor is a three phase affair all prewired to the motor. If the motor is a single phase only L1 and L2 are used. In your case, at the motor tape off L3. Usually the magnetic switch and contactor are powered off L1.

All synchronous motors have a "Frame" style. It is usually listed on the serial number plate. If you buy the same frame style single phase motor you should be OK. Although, in the used market three phase motors are little more than a dime a dozen, the single phase motors are almost nonexistent.

Rich
In furniture 1/32" is a Grand Canyon
NoThankyou is online now  
post #14 of 28 Old 11-13-2018, 05:33 PM Thread Starter
Junior Member
 
niedermee's Avatar
 
Join Date: May 2017
Posts: 9
View niedermee's Photo Album My Photos
I purchased a VFD, but it doesn't seem to be working. I have 230v at the switch, but no lights when I turn on the saw. Has anyone else run a 3 ph. SawStop using a VFD? I spoke with sawstop and the young gun tech support said they can't support troubleshooting my issue if I'm using a VFD on a 3 ph. saw. Hmph.
niedermee is offline  
post #15 of 28 Old 11-13-2018, 06:48 PM
Senior Member
 
Catpower's Avatar
 
Join Date: Jan 2016
Location: Frognot Texas
Posts: 2,197
View Catpower's Photo Album My Photos
Quote:
Originally Posted by niedermee View Post
I purchased a VFD, but it doesn't seem to be working. I have 230v at the switch, but no lights when I turn on the saw. Has anyone else run a 3 ph. SawStop using a VFD? I spoke with sawstop and the young gun tech support said they can't support troubleshooting my issue if I'm using a VFD on a 3 ph. saw. Hmph.



Read the manual with the VFD closely you will probably have some dip switches you have to adjust and a jumper to install on a couple terminals to make the VFD work. The jumper will be where a 1-10 ohm resistor would have been wired for remote frequency control.


Also I would disconnect the motor from the drive until you can verify you are getting 230 on all three legs, or you could end up single phasing the motor which is real bad, it can let the magic smoke out of the motor



That is if the Chinese to English translation is good


Other then that contact the VFD's company
TimPa likes this.

There is no app for experience

Last edited by Catpower; 11-13-2018 at 06:50 PM.
Catpower is offline  
post #16 of 28 Old 11-13-2018, 09:43 PM Thread Starter
Junior Member
 
niedermee's Avatar
 
Join Date: May 2017
Posts: 9
View niedermee's Photo Album My Photos
It’s getting 230v on all 3 legs. Wasn’t single phasing either. It was set up to run @60hz too &#x1f601;. I think we are going to put the VFD on the o-scope and see it it has spikes and check the quality of its output, as we think we may have let the smoke out of one of the components. Argh!
niedermee is offline  
post #17 of 28 Old 11-14-2018, 08:00 AM
Senior Member
 
Join Date: Jan 2010
Location: NW Pa
Posts: 2,886
View TimPa's Photo Album My Photos
I agree with catpower, there are MANY programmable features on a vfd. and one of them incorrectly programmed can screw you.


if it is putting out the 230vac 3 phase, (and there is no current limiting going on) then the you should have lights
TimPa is offline  
post #18 of 28 Old 11-14-2018, 05:30 PM
Village Idiot
 
epicfail48's Avatar
 
Join Date: Mar 2014
Location: Springfield MO
Posts: 4,685
View epicfail48's Photo Album My Photos
Basic thing to check, but most VFDs that ive seen have a knob on the front of the unit to control the frequency output, are you sure that yours is turned up all the way? It could be putting out 230v 3-phase, ust at 25hz instead of the 60hz you need

I need cheaper hobby
etsy.com/shop/projectepicfail
epicfail48 is online now  
post #19 of 28 Old 11-14-2018, 06:26 PM
Senior Member
 
Catpower's Avatar
 
Join Date: Jan 2016
Location: Frognot Texas
Posts: 2,197
View Catpower's Photo Album My Photos
Quote:
Originally Posted by epicfail48 View Post
Basic thing to check, but most VFDs that ive seen have a knob on the front of the unit to control the frequency output, are you sure that yours is turned up all the way? It could be putting out 230v 3-phase, ust at 25hz instead of the 60hz you need



If that was the case the motor would still run but much slower. That is why they are called Variable Frequency Drives, they adjust the frequency to operate a 3 phase motor from 10 Hz to about 200 HZ make that 3600 RPM motor really wind out LOL

There is no app for experience
Catpower is offline  
post #20 of 28 Old 11-14-2018, 06:34 PM
Senior Member
 
Catpower's Avatar
 
Join Date: Jan 2016
Location: Frognot Texas
Posts: 2,197
View Catpower's Photo Album My Photos
Quote:
Originally Posted by niedermee View Post
Itís getting 230v on all 3 legs. Wasnít single phasing either. It was set up to run @60hz too &#x1f601;. I think we are going to put the VFD on the o-scope and see it it has spikes and check the quality of its output, as we think we may have let the smoke out of one of the components. Argh!



You probably won't like the display on the O scope, the VFD converts the DC to a pulsating DC, the sine waves will be square toothed, but that is the way they work, also why you have to use a 3 phase motor, a regular VFD won't work on a single phase motor
woodnthings likes this.

There is no app for experience
Catpower is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Woodworking Talk - Woodworkers Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Similar Threads
Thread Thread Starter Forum Replies Last Post
Single phase vs three phase controllers lukebarber Power Tools & Machinery 3 05-10-2018 06:45 PM
120/240 single phase motors in a 3 phase shop Brian(J) Power Tools & Machinery 3 08-21-2016 11:44 PM
3 phase motor with single phase power Chuck Feathers General Woodworking Discussion 31 06-24-2016 09:31 PM
Three phase table saw to single phase? cck Power Tools & Machinery 8 03-03-2016 08:10 PM
Converting an old Delta unisaw from 3ph power to single phase G_P_K Power Tools & Machinery 12 12-27-2015 07:37 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome