belt speed arithmatic needed

Von Gruff

Gold Membership
#1
I am getting a power upgrade for my grinder and it would be good to know the belt speed that I can get with the new set-up.
I have a 1 hp singe ph motor at present with a 1400 rpm output through a 5 1/2 in pulley driving a 3 1/2 in pulley on a shaft that turns the 4 inch drive wheel.
I am replacing the motor with a 2hp 3 ph motor at 1400 rpm with vfd and have made a new drive wheel that is 5 1/2 in so who is the math wiz who can work out the belt speed from that data.
I am waiting for the electrician to do the wiring when he comes back from holidays but I put the larger drive wheel on with the present motor driving it yesterday when I was doing the primary grind before HT and was surprised just how much quicker it cut so looking forward to the new power unit so I can slow things down for the finer belts.
 

KenH

Well-Known Member
#6
Good numbers from the Count, and with VFD if you overspeed the VFD by 50% to give 2100 RPM you'll have around 4300 SFPM.

If you could go direct drive to do away with the belts by mounting that new 5-1/2" drive wheel direct to motor shaft for smoother running you'd still have around 4,000 SFPM belt speed by doubling the RPM (running the VFD at 120 hz max). You gonna LOVE that VFD!.
 

Von Gruff

Gold Membership
#7
Good numbers from the Count, and with VFD if you overspeed the VFD by 50% to give 2100 RPM you'll have around 4300 SFPM.

If you could go direct drive to do away with the belts by mounting that new 5-1/2" drive wheel direct to motor shaft for smoother running you'd still have around 4,000 SFPM belt speed by doubling the RPM (running the VFD at 120 hz max). You gonna LOVE that VFD!.
The motor output shaft is not quite long enough and I would also have to make a table top extension to site the motor to suit that configuration.
Now that is has been mentioned though, I will HAVE to do some investigation of that scenario. Unfortunately I will have to wait till after the 24th for the electrician come back from holiday
 
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