VFD to tame sander startups?

[Toby Jutras]

Hi folks!
i have a Grizzly G0539 belt sander and I’m right at the max of my power available. Everything runs fine, but the machine shudders at startup and sometimes reboots my PhasePerfect.

Would adding a VFD help to tame the startups? Are there other soft startup options I should consider?

Adding higher amp service to the shop and upgrading the PhasePerfect isn’t in the budget this year, so looking for other options.

thanks,
Toby

[Joe Jensen]

You can program a VFD for soft start which will reduce inrush current. Be careful that the VFD only runs the motor and not any controls.

[Bill Dufour]

How many Hp is the sander? You can either supply it from the phase shifter or direct from house current. Supplied from the shifter it will output full power. from single phase input most will need to be oversized by 40% or so. There are some VFD's that are rated for single phase input including 120 v input.
Bill D

[Bill Dufour]

How long does it take the sander to come up to speed? The general recommendation for a vfd is 3 seconds or more acceleration time just to not overload the mechanical end of lightly loaded stuff. A belt sander probably has more mass to accelerate and should be at the high end or higher. I would let it coast to a stop, no need for a dynamic stop with it's inherent dangers.
Bil lD

[Toby Jutras]

The sander is 15hp, or 50 amps 3 phase. Bypassing the electronic controls, it starts up well. I found this out when a contractor welded shut.

I'm thinking even a soft start module might do the trick. Open to suggestions.

[brent stanley]

Talk with phase perfect, they are very helpful and may be able to give you some thoughts about tweaking caps etc. Also, you could try turning another three phase machine on first on the same circuit. Seems counter intuitive, but the idle machine can help the sander start up.

B

[Bill Dufour]

VFD over 3hp is going to be very costly. Cheaper to buy a 36" disk sander and turn that on before starting the belt sander get a 3 phase dust collector. I doubt you will find a 15Hp vfd under 440 volts.
Bill D

[Andrew Hughes]

The problem sounds a lot like what I’ve been deal with for years. Nothing I could do to improve my soft service until Edison added a 27 kw transformer to my neighbors utility pole. I only had to wait 3 years they also had to put in a bigger pole . I’m glad I didn’t have to pay for that day.
Just in case here’s some numbers for sizing a single phase service.
Size the single phase supply (cord wiring, contactor) upstream from the rpc according to the hp rating of simultaneous client motors. Use NEC table 430.250 to get the ampere value for each simultaneous load motor, based on its HP. Multiply the sum by 250%. Size conductors and contactors for this number. Example: simultaneous 7.5 and 5hp load motors, 230v, the entries are 15.2 and 22 amps. Sum 37.2, x2.5 =93 amps. Yow. But doesn’t need to be a NEMA size 3 or 4 contactor. Just needs to be sized for 93+ inductive amps.


Good Luck

[David L Morse]

the machine shudders at startup and sometimes reboots my PhasePerfect.




Bypassing the electronic controls, it starts up well.

You might want to check the power input wiring to make sure the control circuitry isn't connected to the generated leg.

[Jason Roehl]

VFD over 3hp is going to be very costly. Cheaper to buy a 36" disk sander and turn that on before starting the belt sander get a 3 phase dust collector. I doubt you will find a 15Hp vfd under 440 volts.
Bill D

I have several at work that are 208V 3ph 20HP...but they definitely weren't cheap, probably in the neighborhood of $4000-$5000 each, not installed.

[Bobby Robbinett]

You could probably get a suitable VFD from Jack Forsberg (sp?) for under $1,000.

[Alan Lightstone]

Which Phase Perfect do you have? I have no issues with my Grizzly G0445 Wide-Belt and my Phase Perfect (Both 10 HP versions). If yours are both rated for 15 HP, I'm not sure why you are having an issue.

It might be that Duke Energy installed a mega transformer for my house (due to the large solar array, but it must help with the shop also).

Also, which order do you start your Grizzly? Belt first or Conveyor first? Not sure it matters, but I always go top to bottom, which I think is belt first.

[Bill Dufour]

The problem sounds a lot like what I’ve been deal with for years. Nothing I could do to improve my soft service until Edison added a 27 kw transformer to my neighbors utility pole. I only had to wait 3 years they also had to put in a bigger pole . I’m glad I didn’t have to pay for that day.
Just in case here’s some numbers for sizing a single phase service.
Size the single phase supply (cord wiring, contactor) upstream from the rpc according to the hp rating of simultaneous client motors. Use NEC table 430.250 to get the ampere value for each simultaneous load motor, based on its HP. Multiply the sum by 250%. Size conductors and contactors for this number. Example: simultaneous 7.5 and 5hp load motors, 230v, the entries are 15.2 and 22 amps. Sum 37.2, x2.5 =93 amps. Yow. But doesn’t need to be a NEMA size 3 or 4 contactor. Just needs to be sized for 93+ inductive amps.


Good Luck


You might want to add 5-10% extra to make up for vfd or phaser inefficiency?

[Jared Sankovich]

If you run this off the PP it's a $650 soft start option
435706

[Toby Jutras]

It turns out this was exactly the issue. I had a tool repair person come to the shop to do some testing with me and we found out that voltage drop was significant... down to 95v at startup. The power company treated my issue as an emergency, and replaced my 10kv transformer with a 50kv. Now everything seems to be working much better!

Thanks for the tip.

Toby


Which Phase Perfect do you have? I have no issues with my Grizzly G0445 Wide-Belt and my Phase Perfect (Both 10 HP versions). If yours are both rated for 15 HP, I'm not sure why you are having an issue.

It might be that Duke Energy installed a mega transformer for my house (due to the large solar array, but it must help with the shop also).

Also, which order do you start your Grizzly? Belt first or Conveyor first? Not sure it matters, but I always go top to bottom, which I think is belt first.