Question about a new grinder spin up time

Jan 12, 2007 5 Replies

I bought a low priced 8" grinder off of Ebay. It says it's 3/4 HP. Has the standard coarse and fine grey wheels. When I turn it on it takes about 1 minute to come up to speed, and while it is spinning up, the least pressure on a wheel will make it stop. It seems to be stable while running, but I never saw an electric motor take so long to come up to speed. Is this normal? Joe



Joe, I'll go out on a limb here and say "no".

Bum starting capacitor? False power label?

Particularly on the larger wheel, the same gearing that reduces speed should torque. Apparently your grinder is operating with total disdain for that subset of the laws of physics. It should take, one would think, a pronounced effort to stop a 3/4 hp motor spinning a couple of flywheels.

Bill

I'd suspect the start capacitor or possibly that the motor is a 110/220V motor wired for 220V and running on 110V. 3/4 HP is small for a dual voltage motor but the do exist.

Hi Joe

Return that grinder Joe, and get an other one, and do try it in the store if you are able to, not so when having it shipped to you of course.

I have a grinder with a 1 HP motor with 2 10" wheels 1" wide, it will take under 2 seconds to come to full speed, I can say twenty-one and it is just about at full speed,and it is also a chaiwan mini horse, my other grinder is a 1/3 HP Stanley grinder and it is basically at full speed when you pull your hand back from the switch, like almost instantly. The grinders should also not stop when grinding normally, my grinders will slow somewhat but they do not stop when I'm grinding heavier than what I would do to sharpen my tools.

Have fun and take care Leo Van Der Loo

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snipped-for-privacy@gmail.com wrote: > I bought a low priced 8" grinder off of Ebay. It says it's 3/4 HP. Has > the standard coarse and fine grey wheels. When I turn it on it takes > about 1 minute to come up to speed, and while it is spinning up, the > least pressure on a wheel will make it stop. It seems to be stable > while running, but I never saw an electric motor take so long to come > up to speed. Is this normal? > Joe

I agree with the group consensus - not normal. Probably bad start capacitor, if it is guaranteed, replace it, if you are stuck, open it up and try a new capacitor (and check that the starter switch is working) and check if it's dual voltage and wired for 220 - or maybe it's single voltage 220 - that will make it act exactly like you report

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