Pm Planer/Grizzly Jointer Score + Is Grizzly sliding attachment worth 50% off??

[Patrick Irish]

In the middle of making arrangements to pick up the 1960's Pm 160 Planer I scored on an auction site, a Grizzly 8" G0490x jointer popped up locally on Craigslist for $800. I called, offered $700 and he said yes

Friday my Dad and rented a massive budget truck with a lift gate so lower the 1,100lb planer in my driveway. I bought from a local parks department from an auction site. They forklifted it. We almost lost if off the tailgate while it was on the pallet jack

The jointer was a piece of cake moving around. I think I need to check alignment this coming weekend.

My question:

Is a used Grizzly T10223 sliding table attachment say for $200 a good deal? I do not have room for it right now but should when I move.

Pics of jointer and PM Planer cuz I had to

The planer is a 3 phase 5hp. I think I'm gonna go the VFD route instead of a rotary phase converter.

[Earl McLain]

Nice scores!! That jointer looks new, and the spiral head too.

Will be interested and watching to see what you come up with on the VFD at 5 hp. There's a table saw not far from me that has a 5 hp 3ph, looking inexpensive right now--but single phase in to 5hp 3ph out is looking rare and expensive on a brief search yesterday. IF (big if) I do the bidding on the TS--I'd be able to use a static converter instead, as the 2/3 power would still be plenty in a table saw. Not sure a planer would be okay with the loss.
earl

[Adam Merritt]

I believe you can still run a 5HP 3ph VFD on single phase, you just derate the power similar to using a static phase converter. I was contemplating a 5hp PM66 before I bought my 3hp SawStop and was looking at this exact situation. I was talking with an industrial electrician friend about options and we decided that in theory a 7.5HP 3ph VFD should run at basically 100% power, even though it was unlikely I would need it. I didn't end up going this route, and can't validate the claim as such, but the price difference from the static to VFD was around $200 more if I recall, whereas the rotary phase converter was $1000k or so more.

[Malcolm McLeod]

I believe you can still run a 5HP 3ph VFD on single phase, you just derate the power similar to using a static phase converter. I was contemplating a 5hp PM66 before I bought my 3hp SawStop and was looking at this exact situation. I was talking with an industrial electrician friend about options and we decided that in theory a 7.5HP 3ph VFD should run at basically 100% power, even though it was unlikely I would need it. I didn't end up going this route, and can't validate the claim as such, but the price difference from the static to VFD was around $200 more if I recall, whereas the rotary phase converter was $1000k or so more.

There seems to be a LOT of SMC discussion and mistaken perceptions about "derating" of motors/power/VFDs/etc lately. I won't claim to be the world's leading expert, but will try to explain as I understand it. 'Derating' of a VFD supplying any motor relates to the size of the components in the VFD. It applies to the VFD, not the motor or the process load.

Consider the 5Hp (230Vac) above. Standard current draw for a 230Vac 5Hp motor is 15.2Amps (3 phase) or 31Amps (1 phase). If you put 5Hp worth of load on this 5Hp motor, it WILL attempt to pull 15Amps from the VFD output and the VFD will try to pull 31Amps from the supply panel.

Typically a VFD rated for 5Hp/230Vac/3-ph will include internal circuits sized to handle 15.2 Amps (plus some margin for overload, but lets ignore this for the moment). If you find a VFD rated for 5Hp/230Vac/1-ph, it will include internal circuits sized to handle 31 Amps. As you can imagine, the 1-phase circuits and the components used in them will likely be much larger - - and also fairly rare, since so few installations require this much Hp on 1-phase.

If you buy a 5Hp/3-ph VFD and want to supply it with a 1-phase input, it's components are only designed to handle ~15 Amps (again, ignoring any OL margin). The 1-ph input will draw 31Amps, but the output will rearrange this power into 3-ph at ~15Amps. The input amperage will be well above the VFD's design capacity, so the it needs to be derated. In this case, 15Amps 1-ph is ~3Hp. You 'derate' it either by installing a 3Hp motor, or configuring the VFD parameters to only allow the motor to produce 3Hp (either by limiting the speed or current draw).

Several smaller VFDs are advertised as 'suitable for 1-ph operation'. This just means the manufacturer picked internal components that can handle the increased amperage (margin) associated with 1-phase operation - - without derating the VFD.

[Bill Dufour]

My lathe came with a VFD rated for 1hp. It is driving a 3hp motor but, I have not taken any big cuts. So you could run that 5hp motor from a 3hp vfd if you limit the current to the vfd maximum. Do you really need 5hp or would 3hp be enough for you?
For myself as a hobby shop user I do not think I want 5hp. I do not saw much over 2x stock so I figure it is a litle safer to have the saw bog down on deep cuts to warn me rather then grab and throw the wood around with the power of 5 horses.
Bill

[Bradley Gray]

I have never used a VFD, but have run rotary converters for 40 years. Rotary converters are basically an extra 3 phase motor that runs without load on single phase and acts as a generator to create the 3rd leg. All one needs is a way to get it spinning and you have 3 phase power. I use capacitors to start my converter but a small single phase motor with a slip clutch also works. A machinist friend ran his whole shop on an idler that he stared by spinning the pulley with his foot.

[Patrick Irish]

There seems to be a LOT of SMC discussion and mistaken perceptions about "derating" of motors/power/VFDs/etc lately. I won't claim to be the world's leading expert, but will try to explain as I understand it. 'Derating' of a VFD supplying any motor relates to the size of the components in the VFD. It applies to the VFD, not the motor or the process load.

Consider the 5Hp (230Vac) above. Standard current draw for a 230Vac 5Hp motor is 15.2Amps (3 phase) or 31Amps (1 phase). If you put 5Hp worth of load on this 5Hp motor, it WILL attempt to pull 15Amps from the VFD output and the VFD will try to pull 31Amps from the supply panel.

Typically a VFD rated for 5Hp/230Vac/3-ph will include internal circuits sized to handle 15.2 Amps (plus some margin for overload, but lets ignore this for the moment). If you find a VFD rated for 5Hp/230Vac/1-ph, it will include internal circuits sized to handle 31 Amps. As you can imagine, the 1-phase circuits and the components used in them will likely be much larger - - and also fairly rare, since so few installations require this much Hp on 1-phase.

If you buy a 5Hp/3-ph VFD and want to supply it with a 1-phase input, it's components are only designed to handle ~15 Amps (again, ignoring any OL margin). The 1-ph input will draw 31Amps, but the output will rearrange this power into 3-ph at ~15Amps. The input amperage will be well above the VFD's design capacity, so the it needs to be derated. In this case, 15Amps 1-ph is ~3Hp. You 'derate' it either by installing a 3Hp motor, or configuring the VFD parameters to only allow the motor to produce 3Hp (either by limiting the speed or current draw).

Several smaller VFDs are advertised as 'suitable for 1-ph operation'. This just means the manufacturer picked internal components that can handle the increased amperage (margin) associated with 1-phase operation - - without derating the VFD.

So cliff notes if I understand correctly and from what I've read over the past week..... A 1 phase input to 3 phase output VFD is hp=hp vfd to machine? Meaning, there is no derating and no needing to get a larger VFD? 1 phase in 3 phase output 5hp VFD SHOULD power my 5hp planer at 5hp full load. I'll never need that as I typically only take off a 1/32" each pass.

If I had a 3 phase input to a 3 phase output, the power to the machine would be derated by 1/3. Similar to a rotary phase converter, in order to power a 5hp machine, I would need to get a 10hp rotary phase converter.

I'm on the fence about putting together rotary converter. It can be done for easily under $300 depending on price of a 10hp 3 phase motor. I just don't think I have the room in my 2 car garage for a motor/panel PLUS I'm not sure if a rotary phase converter (RPC) can be wired with an extension cord so I can plug into the dryer outlet when needed and then unplugged when I need to run the dryer.

[Malcolm McLeod]

So cliff notes if I understand correctly and from what I've read over the past week..... A 1 phase input to 3 phase output VFD is hp=hp vfd to machine? Meaning, there is no derating and no needing to get a larger VFD? 1 phase in 3 phase output 5hp VFD SHOULD power my 5hp planer at 5hp full load. I'll never need that as I typically only take off a 1/32" each pass.

If I had a 3 phase input to a 3 phase output, the power to the machine would be derated by 1/3. Similar to a rotary phase converter, in order to power a 5hp machine, I would need to get a 10hp rotary phase converter.

I'm on the fence about putting together rotary converter. It can be done for easily under $300 depending on price of a 10hp 3 phase motor. I just don't think I have the room in my 2 car garage for a motor/panel PLUS I'm not sure if a rotary phase converter (RPC) can be wired with an extension cord so I can plug into the dryer outlet when needed and then unplugged when I need to run the dryer.

I think you have this backwards (if I'm following you).

For a VFD with 1-ph IN and 3-ph OUT, you need to get a VFD larger than the motor. The VFD is typically derated (i.e buy a 7.5Hp VFD to supply a 5Hp motor). You still get full rated 5Hp from the motor and the input side of the VFD does not carry more current than it was designed to handle. (Exact VFD size may depend on the specific manufacturer's specs - - so please double check.)

In most situations using 1-ph input to the VFD, multiply the 3-ph motor Hp by 1.7 (sq root of 3). This will tell you the size VFD you need. But again, double check with manufacturer.

[Don Jarvie]

If the motor is not direct drive then look into a swap out for a 3hp motor single phase. The bay has plenty to choose from. Make sure it's the right frame since PM uses C frame motors (no motor mount). Shaft isn't as important since you can swap out the pulleys easy.

You may need to upgrade the starter since 3 phase pull less amps and the starter may not cover the amps. OWWM has tons of info about this stuff.

in the long run it may be easier to swap everything out.

[Malcolm McLeod]

You asked for cliff notes (see above), so I'll add this separately:

Ignore all the complications of slip, power factor, efficiency, service factor, etc.... and just look at power in and out of a given device:

If your process pulls 5 mechanical horsepower out of the motor, you have to put 5 electrical horsepower into it. If this is via 230V/3ph, it means about 15Amps.

This has to come from the VFD, so you design the output side of the VFD to safely deal with 15A/3ph (::5 Hp). Now the INPUT side of the VFD has to receive 5Hp via 1ph power. So 5Hp at 230V/1ph equates to 31Amps, and the components in the VFD must be designed to deal with this much current. For most VFDs, 31Amps equates to a 7.5 or even 10Hp, and that's why you derate the capacity of the VFD.

I've no experience at all with RPCs, but I think most of the 'de-rating' assumptions are based on this. If I have been listening properly, a 5Hp motor can't actually produce it's full, rated power because of a limited power supply from the 3rd leg of the RPC - - - effectively de-rating the motor....?

VFD's won't limit a motor's rated power output, assuming 2 things: 1) you don't program it to do so; and, 2) you don't melt the VFD trying to pull too much juice thru it.

Edit: My references to 15A & 31Amps are out of standard tables for FLA of 5Hp motors - YMMV.

[Bill Space]

Malcolm said:

"For a 3 phase VFD with 1-ph IN and 3-ph OUT, you need to get a VFD larger than the motor."

I added the red text to his sentence. I am certain Malcolm was referring to a VFD that is designed to use three phase power on the input size. As I think he mentioned above, a VFD designed to operate with single phase input power would be sized to match motor horsepower.

Bill

[Malcolm McLeod]

Malcolm said:

"For a 3 phase VFD with 1-ph IN and 3-ph OUT, you need to get a VFD larger than the motor."

I added the red text to his sentence. I am certain Malcolm was referring to a VFD that is designed to use three phase power on the input size. As I think he mentioned above, a VFD designed to operate with single phase input power would be sized to match motor horsepower.

Bill

Bill, thank you - - you are correct. The context of this thread revolved around a 3-phase load, so I assumed a 3-phase VFD.

While we're being syntactically persnickety, I'll offer another word (or 12) of caution: Lots of import VFDs will boldly say "designed for 1-phase input". Somewhere in literature it may also say 5Hp/3ph (3Hp/1ph). It will function on 1-ph, but is 3-phase and may need to be de-rated because of the ampere draw.

If the VFD's input and output don't share the same phasing, you have to look at the specifications. ...Read the manual before purchase.