3ph 3 hp PM66- new motor or vfd?

[David Kumm]

Patrick, you need to do a lot more homework before wiring up a machine. A three phase motor of equal hp uses a little more than half of the amperage of its single phase replacement. therefore you may need to replace the starter with one of larger size. See my earlier post. Because the amperage doubles, you will also need to size the overloads ( heaters ) in the starter for the new motor. I'm also assuming that the new motor is the same frame size and has the same length shaft so the pulleys ( sheaves ) will fit and the belts won't need to be swapped. Dave

[Andrew Seemann]

Replacing the motor with a single phase motor and putting a new starter on will probably cost you more than a VFD, but at the same time, you will never need to think about it again or replace it in your life. Not sure if you can say the same about a VFD off eBay. Just something to think about.

[Patrick Curry]

<p>

Patrick, you need to do a lot more homework before wiring up a machine. A three phase motor of equal hp uses a little more than half of the amperage of its single phase replacement. therefore you may need to replace the starter with one of larger size. See my earlier post. Because the amperage doubles, you will also need to size the overloads ( heaters ) in the starter for the new motor. I&#39;m also assuming that the new motor is the same frame size and has the same length shaft so the pulleys ( sheaves ) will fit and the belts won&#39;t need to be swapped. Dave

A starter as in a motor switch, correct? &nbsp;I was counting on a replacement switch or starter to match the higher amperage of the single phase. $25 or so.</p>

[Matt Day]

Dave means a starter, not just a “switch”. By starter that means magnetic starter - the benefit is that if the power shuts off while cutting, it won’t turn right back on when the power comes back on. Magnetic starters for 3hp will cost about $100+.

http://www.grizzly.com/products/Magnetic-Switch-Single-Phase-220V-Only-3HP-21-25A/T24101

[Dan Friedrichs]

Patrick, are you typing your replies in some other program, then copy/pasting them into the text box on this site? Your posts contain formatting characters because of that.

[Patrick Curry]

Patrick, are you typing your replies in some other program, then copy/pasting them into the text box on this site? Your posts contain formatting characters because of that.

Dan, I was typing my replies through an IPad which for some reason doesn't play well with this website. Very annoying. Commas, apostrophes and other non-alpha characters are converted into those strange symbols, and then also my replies were not attached to the post I was responding to. I'm on my desktop now.

[Geoff Crimmins]

Magnetic starters for motors are designed to work with several sizes of motors, with the interchangeable heaters (overloads) sized to the amp-rating of the specific motor it's being used with. There are several sizes of starters (00, 0, 1, 2, etc.) that each work with a certain range of motors. It may be that that the starter on your saw is sized to work with both 1-phase and 3-phase 3hp motors, in which case you'll only need to change the heaters, which isn't especially expensive or difficult. Or it may be that the starter on your saw is sized to work with the 3-phase 3 hp motor, but is too small for use with a single-phase 3hp motor, in which case you'll need to replace the starter (or use a smaller motor.) With the saw unplugged you can remove the cover from the starter on the saw. Inside the cover there should be a chart of heaters that will work with the starter. Check the amp rating on the single phase motor, and see if that number appears on the chart of heaters. If it does, then you just need new heaters. If you're comfortable doing this yourself, you can always hire an electrician that works with electric motors. In any case, the PM66 is a great saw and I expect you will be very happy with it when you get it running.

--Geoff

[Patrick Curry]

Magnetic starters for motors are designed to work with several sizes of motors, with the interchangeable heaters (overloads) sized to the amp-rating of the specific motor it's being used with. There are several sizes of starters (00, 0, 1, 2, etc.) that each work with a certain range of motors. It may be that that the starter on your saw is sized to work with both 1-phase and 3-phase 3hp motors, in which case you'll only need to change the heaters, which isn't especially expensive or difficult. Or it may be that the starter on your saw is sized to work with the 3-phase 3 hp motor, but is too small for use with a single-phase 3hp motor, in which case you'll need to replace the starter (or use a smaller motor.) With the saw unplugged you can remove the cover from the starter on the saw. Inside the cover there should be a chart of heaters that will work with the starter. Check the amp rating on the single phase motor, and see if that number appears on the chart of heaters. If it does, then you just need new heaters. If you're comfortable doing this yourself, you can always hire an electrician that works with electric motors. In any case, the PM66 is a great saw and I expect you will be very happy with it when you get it running.

--Geoff

Geoff,
A big thank you for the information. I'll check the existing starter on the TS tonight to see if it would work for a single phase replacement motor. (Baldor $385)

I also found the correct VFD (TECO FM50-203C $200). The VFD would save me a bit of money but I'm going to watch the installation video before making any decisions.

Yes, I'm excited to get the PM up and running . It has the old style fence but I believe it to be in good working order since the shop teacher had been using it. He ordered the saw for the middle school in 74' and took it out of commission when they closed shop in the mid 80s but kept the saw there for school needs. They closed the school down and now he has a garage filled with PM 3 phase equipment! He invited me to keep loading my trailer with low ball prices but I somehow managed to show some restraint.

[Tom Trees]

<p>
Hi Paddy Currently running a 3 phase 3 hp motor on my tablesaw with no issues. I have both of the cheapest VFDs you can get, costing around a hundred quid each. These inverters are the Huanyang 2.2KW or 3HP VFD /inverter tomato/tomato. Both look the same, but the newer ones are quiet (auto shut off cooling fan technoligy) Depending if your the type that would be annoyied by a fan, I would probably go with the cheapest and newer(I think) Isacon/askpower drive again. Im big into safety switches, you will need to either copy Carl Holmgrens design on his TS, or buy a 5 quid relay to enable a stop station ... A stop station (a green start and a red stop switch) is called three wire control. You can buy these switches for like a quid or so a piece on the bay. What your looking for is a green NO (normally open) switch/button, and a red NC (normally closed) the cheapest you can find. I actually have to buy a relay yet for my bandsaw, as I have just wired a light switch for now. I made some brackets and affixed them to the TS, to have a board hung by an old door hinge. There is a dowel protruding out the back of the board to hit the stop switch, and a hole beside it for the start switch.... (which is very safe, as you cant turn it on if your fingers are too fat to go into the hole, because you will be hitting the stop too, at the same time, so it wont work). I have the parameters for the Huanyang and the Isacon/Askpower 3HP/2.2KW drives (you would probably be able to find my threads, of you cant ask me) The most effort is making the cabinet for the VFD to go in, and making a box for the two switches if you dont buy the expensive button stations. Here are some photos</p>

[Bill Dufour]

What your looking for is a green NO (normally open) switch/button, and a red NC (normally open) the cheapest you can find.

Correction: red stop should be normally closed. NC
Bill D

[Tom Trees]

<p>
Thanks Bill Getting late here [IMG]</p>
<p>
https://www.sawmillcreek.org/clientscript/ckeditor/plugins/smiley/images/images/smilies/smile.gif[/IMG] Well spotted!</p>
<p>
Mistake sorted</p>

[Bill Dufour]

If you have a three wire control system it is easy to add another stop switch in series. maybe on the back end of the machine.
Bill D

[Bill Dufour]

Vocabulary lesson on motor control. feel free to let me know if I get things wrong. This is for a real industrial type push button station control system.

Switch= push button, low amps may be 240/120/24 volts. There can be multiple switches anywhere you want them.

Contactor=relay to turn power on/off to the motor. May also contain extra low voltage switches for control wiring

Overloads=(optional but strongly recommend) downstream of the contactor. Circuit breaker that shuts down if amp draw is too high. It also has extra low voltage control switches.
Two kinds of overloads= the old type with a replaceable heater for each line. the heater is sized for load amps. The newer type has an adjustable heater that can be turned within a range of amps.

Motor starter= contactor+overloads wired together in one box. there may be a transformer if lower voltage controls are used.


For some reason my $105 VFD has to use a stop switch which is NO so adding extra stop switches Is problematic. I have to make sure the Contact block has NO as well as the more standard NC for stop switches. To be honest i have not really figured out the stop method. right now my lathe is wired forward and reverse with it stopping in neutral. The manual is terrible and it mentions Jog speed etc but not how to activate the jog function.
It also mentions three or four stop modes but not how to activate "stop" function.

One big advantage of a real motor control is if the power goes out for a second the tool shuts off until the go button is pushed again. No worrying, with the lights out, how to turn off the machine before it restarts and bites you.

Bill D

[Bill Dufour]

If your existing motor control uses a 208 volt coil that should work fine on 240. Most likely there is a transformer that may need to have a jumper moved on the input side. I would think it is probably 24 volt control.
I have used lighted stop switches to make it easy for anyone to figure how to turn off the machine. Green not so much. If you do not know how to turn it on you should not be using it. But if something bad happens I want anyone to quickly figure out how to turn it off

[Tom Trees]

Have you got the isacon/Askpower drive too Bill?
I probably will be getting another in some distant time ahead for tablesaw no 2, or whatever I may stumble across.
I was looking for a relay for the old Huanyang drive I have, at the time, I did not know the relay was in the terminals allready for the switches.
Unfortunatly the Isacon/askpower drive does not seem to have this, so I put it on the bandsaw instead, as I wanted the saftey of the handsfree paddle style switch
on the TS.
I stuck a regular light switch on the bandsaw cabinet for the moment ...
I dont have an isolator switch to provide power to my machines, instead I just plug them out, so this light switch has nothing to do with
mains power, those other switches are now redundant for the time being.
Make sure you get a single phase in VFD by the way.