Another few magnetic starter questions

[James Goodman]

I have a 12"-14" Delta table saw that I am fixing up and am going to change out the 5 HP 3-phase motor to a 5 HP 1-phase motor. I've spent days agonizing over this decision (I know, get a life), evaluating RPC and VFD options and this is the best route for me to go. I can do basic wiring and follow instructions, so I'm not helpless, but I have a few quesitons about motor protection and human protection related to the motor protection.

QUESTION #1 - My intention was to connect the new motor to a magnetic starter (with integral thermal overload protection) and then run a circuit from the starter to a new 30-amp dual-pole breaker in the main panel. And I know a magnetic starter will act as a safety if power goes off and quickly comes back on again, so that the saw will not come back on with power restoration. So, in hunting around on the web for the appropriate magnetic starter, I have read some posts on other sites talking about "motor circuit protectors" which are discussed as being superior to magnetic starters. If I understand correctly, these devices act as both a magnetic starter and thermal overload protector......the same functions as a traditional magnetic starter.....but they also incorporate a short-circuit protection function like the circuit breaker in the panel AND adjustable overload protection that would react much faster than the 30 amp breaker in the panel. The installation is also simple. I am not clear about whether the "starter" function of this device includes the magnetic starter AND thermal motor overload protection as half of the function, and then short circuit protection AND circuit thermal overload (not motor overload) protecdtion. This is a link to a discussion on an engineering site:

https://www.eng-tips.com/viewthread.cfm?qid=475660
I do not fully understand it because the terminology used does not clearly distinguish (for me) between the different types of devices.

Here is a link to the device I'm considering.
DEVICE - https://www.superbreakers.com/schnei...v2me32-starter
DEVICE ENCLOSURE - https://www.superbreakers.com/schnei...waAseAEALw_wcB

QUESTION #2 - The other part of my question has to do with the motor. I'm looking at a WEG motor, which will be fine for my purposes and half the cost of a Baldor motor. In the specs of the motor, it says "No overload protection". My question is, what do I need to do to provide overload protection? Does the magnetic starter or a "motor circuit protector" I discussed above the overload protection? If my 3HP motor on my other tablesaw, a Delta Unisaw shuts down from overheating, it starts back up on its own without any kind of device reset in 20-30 minutes. So, what, if anything beyond the magnetic starter do I need to do to protect a motor without built-in thermal protecdtion?

Here's a link to the motor:
https://www.weg.net/catalog/weg/US/e...ted/p/14165571

Thanks very much.

[Brian Holcombe]

I swapped the motor in my tablesaw from a 1.5hp single phase to a 3hp 3ph and run it with VFD. I built the VFD into the machine and run push button controls, safety stop and disconnect. I plug it into a 220v outlet and run it no differently than if it were single phase.

It has the added benefit of starting and stopping as Fast as I desire and I can dial in the speed as needed to suit the blades I run. I have it set to stop within 2 secs even when carrying a 5/8” dado stack.

This is a better way, in my opinion, than replacing a good 3ph motor with a 1ph motor and I’m very happy with it.

The hitachi VFD will shut off in a scenario where there is a draw beyond the motor spec.

I’ve also built out a standard 3ph motor starter system and once all the parts are considered its only slightly more expensive to buy the VFD.

[Patrick Irish]

I was in your boat with an older 5hp 3 phase planer. I initially tried a cheap Huang (spelling) VFD. At the time it was the only VFD that could take 220 in and convert it to power a 5hp motor. Only one that would not exceed a large amp draw. Many other VFDs would work but only power the motor 2/3 or Id have to buy a VFD that was 1.5x what I needed. Long story, the cheap VFD ended up popping one day. Super loud. It didn't help that I was sharing my dryer outlet with it. VFDs like to be plugged in and left alone. More expensive ones and built better.

I opted for a 5hp single phase motor. Amp draw was more but my panel and single use shop was fine. I had to toss the original mag starter motor is the contactors ( I think) inside we too small to power a 5hp single phase. I went with something like this below and re-used the on/off switch on the planer. Works great.

https://www.amazon.com/Magnetic-Elec.../dp/B00ATCCYXK

[James Goodman]

I swapped the motor in my tablesaw from a 1.5hp single phase to a 3hp 3ph and run it with VFD. I built the VFD into the machine and run push button controls, safety stop and disconnect. I plug it into a 220v outlet and run it no differently than if it were single phase.

It has the added benefit of starting and stopping as Fast as I desire and I can dial in the speed as needed to suit the blades I run. I have it set to stop within 2 secs even when carrying a 5/8” dado stack.

This is a better way, in my opinion, than replacing a good 3ph motor with a 1ph motor and I’m very happy with it.

The hitachi VFD will shut off in a scenario where there is a draw beyond the motor spec.

I’ve also built out a standard 3ph motor starter system and once all the parts are considered its only slightly more expensive to buy the VFD.

Thanks for your response. I know the VFD is a viable option and I'd like that as my first choice, but I just do not understand how to wire them or set the parameters, in particular, the inexpensive ones such as you find on Amazon. I've read the manuals of the cheap ones and also the name-brand ones and they are all complete Greek to me. I'm an idiot.....I just don't understand them. So I'd need to buy a Toshiba or Hitachi or ABB to get an intelligible manual for an electrician to follow and then I'd have to hire an electrician to install it. By the time that's all said and done, I'll be out $1200-$1500 at the minimum and I can do the 1-phase motor for about half that.

[James Goodman]

I was in your boat with an older 5hp 3 phase planer. I initially tried a cheap Huang (spelling) VFD. At the time it was the only VFD that could take 220 in and convert it to power a 5hp motor. Only one that would not exceed a large amp draw. Many other VFDs would work but only power the motor 2/3 or Id have to buy a VFD that was 1.5x what I needed. Long story, the cheap VFD ended up popping one day. Super loud. It didn't help that I was sharing my dryer outlet with it. VFDs like to be plugged in and left alone. More expensive ones and built better.

I opted for a 5hp single phase motor. Amp draw was more but my panel and single use shop was fine. I had to toss the original mag starter motor is the contactors ( I think) inside we too small to power a 5hp single phase. I went with something like this below and re-used the on/off switch on the planer. Works great.

https://www.amazon.com/Magnetic-Elec.../dp/B00ATCCYXK

Very helpful, thanks very much!

[Bill Dufour]

What arbor size, can it be switched out? Mine came with 7.5 Hp 3phase. I am now running 2hp single phase. Then pulley spacing is an oddball no longer made so do not lose the motor pulley. Lucky mine was taper lock so I switched the inner portion to fit my new smaller motor shaft. I just use two link belts.
Be careful the side wing is 90,or maybe 60, pounds each. I believe the top is around 160 pounds. Too heavy for one man.
Bill D.

https://sawmillcreek.org//showthread...knife-retrofit


https://www.practicalmachinist.com/f...or-ccw.363944/

[Bill Dufour]

Changing the arbor bearings was pretty easy, with the top off, once I had the correct deep socket. It needed one so I did both. I prefer new sealed bearings to 50 year old shielded ones with dry grease.
Bill D

[Bill Dufour]

I used. a block of 4x6 and moved the switch forward about ten inches so I could see it when running the saw

[James Goodman]

I used. a block of 4x6 and moved the switch forward about ten inches so I could see it when running the saw

Thanks Bill. Well, I've posted this question on Lumberjocks too, and now a couple of very patient contributors over there have succeeded in convincing me to go the VFD route, so that's what I'm planning on doing. In answer to your question about my saw, FWIW, the blade arbor extension is actually the 1" size and not the original 1.125" , so my off the shelf blade selection is greater and easier to find. I appreciate your insights on changing the bearings, because that is something I intend to do as I rebuild it And I have a compact Kubota tractor with 48" pallet forks, so I use that to lift the top (and the saw, for that matter) so that is not too much of a problem.

[Jacques Gagnon]

James,

You may already know this, but just in case…

A 5hp single phase motor requires some time off between starting cycles (many people recommend no more than 5-6 cycles per hour, more or less with 5 to 10 minutes between each cycle. Should you choose to go that route means that you may have to wait much longer than you would like before you start the saw again after shutting it off.

My understanding (others will correct me if I am wrong) is that running the 3 phase motor with a VFD would not impose this limitation on you.

Regards,

Jacques

[James Goodman]

James,

You may already know this, but just in case…

A 5hp single phase motor requires some time off between starting cycles (many people recommend no more than 5-6 cycles per hour, more or less with 5 to 10 minutes between each cycle. Should you choose to go that route means that you may have to wait much longer than you would like before you start the saw again after shutting it off.

My understanding (others will correct me if I am wrong) is that running the 3 phase motor with a VFD would not impose this limitation on you.

Regards,

Jacques

Thank you Jacques, I did not know that.

[Bill Dufour]

You can use the original switches to control the low voltage VFD if you like them or add new ones. I would consider adding an extra off switch on the back or side just in case.
Mine was built around 1965 and the cast iron motor used an old NEMA bolt spacing. I had to make an adapter plate of plywood to mount a newer single phase motor. Of course this meant the old belts did not fit. I was just able to get it to lower all the way down and not have the capacitor hit. I think that made the belt fit further off.
Bill D
Bill D

[Brian Holcombe]

Thanks for your response. I know the VFD is a viable option and I'd like that as my first choice, but I just do not understand how to wire them or set the parameters, in particular, the inexpensive ones such as you find on Amazon. I've read the manuals of the cheap ones and also the name-brand ones and they are all complete Greek to me. I'm an idiot.....I just don't understand them. So I'd need to buy a Toshiba or Hitachi or ABB to get an intelligible manual for an electrician to follow and then I'd have to hire an electrician to install it. By the time that's all said and done, I'll be out $1200-$1500 at the minimum and I can do the 1-phase motor for about half that.

It took some figuring for me and Malcolm McLeod gave me a lot of guidance. In addition I contacted Hitachi support, they were excellent. Now that I‘ve done that on two machines and have built out 3ph control boxes for three others I’m getting to the point where I would not want to go back to 1ph on anything.

[Tom Bender]

In general you want power thru a saw mounted switch for safety. I turn this off when not in the shop. From this switch go directly to the VFD then on to the motor. For on and off you can use any type of switch because the control circuit coming out of the VFD is low voltage. For my saw it is a foot switch which frees my hands which is especially helpful when stopping the blade.

It can be very nice to slow the blade from screaming fast to gentle purring.

Starting and stopping often can be a problem for a motor connected to a big inertial load like a fan or grinder but not so much for a TS. As mentioned, a VFD provides a soft start so the problem goes away. That's good since I often start mine 6 times a minute.