4 1/2" angle grinder wheel rpm?

[Taul Paul]

Does anyone know the actual general wheel RPM on a 4 1/2" angle grinder. I've seen 10 000 mentioned but
I find it hard to believe. Plan is to use one as a motor power source but I can't if it runs at that speed.

TP

 

[novocaine]

10k is about right give or take a few hundred.
discs are rated to 12,500rpm.
the motor runs at considerable less at around 3000rpm for a 2 pole 50hz motor.

 

[Inspector]

Ours run 11,000rpm on 60 cycle power. Yours will be a little slower because of the 50 cycle you use. The motors are like router motors so are geared down to get there.

Pete

 

[Chippymint]

In order to calculate this by formula, in addition to the diameter you would need to know what the Surface Feet per Minute is. In general saw blades have a 10,000 SFM which is the desirable speed to run a saw blade (This may be where you get your thought from).

From general information 4.5 inch diameter blades can have a rpm of 8000 but I must emphasise this is a guide and could range either side of this. Manufactures would have the information so give them a call.

 

[Taul Paul]

Ah right. Getting it down to 300 rpm is a none starter then. Bin that Idea.

 

[Nelsun]

The slowest grinders I've come across (variable speed Makita and Festool ones) start at 3,000 - 3,500rpm. I'm saying this in case the "300" above was missing a zero as that's really slow.

 

[Taul Paul]

The slowest grinders I've come across (variable speed Makita and Festool ones) start at 3,000 - 3,500rpm. I'm saying this in case the "300" above was missing a zero as that's really slow.

Yes 300 is the target. I'm going to have to buy a 1400 rpm motor and pulley that down. 350 actually works as a 4 to 1 reduction so I'll go with that.
Thanks

 

[Limey Lurker]

10k is about right give or take a few hundred.
discs are rated to 12,500rpm.
the motor runs at considerable less at around 3000rpm for a 2 pole 50hz motor.

AFAIK, all corded angle grinders use a brushed motor, because to reach a speed of 10,000 RPM at the disc spindle requires a motor speed much higher; probably three times higher, which is not attainable by an induction motor.