97-10 Running In Reverse

[amuckart]

If there are two brushes, and you swap the brush casings (and therefore the wiring, and polarity relative to the field coils) then the motor will run backwards.

[Gregg From Keystone Sewing]

I usually try to take the easy way out & if you cross the belt going to the head this will let your reverse rotation motor run the right way,You might have to buy a longer belt or splice it.They grip better when crossed too.

Bob

1st thing I thought of as well. I remember all the 97-10s I've seen running have the belt crossed up like this.

[CowboyBob]

The leather belt will grip better when crossed too!

Bob

[steveh]

I usually try to take the easy way out & if you cross the belt going to the head this will let your reverse rotation motor run the right way,You might have to buy a longer belt or splice it.They grip better when crossed too.

Bob

BoB,

Could you please explain "cross the belt"? Do you mean to to put the belt in a figure eight from the drive pully to the machine pully?

Thank You

Steve

[TwinOaks]

Yes, a half twist in the loop....which makes a figure 8 and changes the direction of rotation.

[sandyt]

Hi Art,

But are you using that running capacitor overthere also? In case of 3 phase motors ofcoarse to run on a 1 phase circuit? Steinmetz circuit? Very few people know about it overhere. Most of them think a 3 phase motor can not run on a one phase cicuit. You will loose a lot of torque, but it's still way enough for sewing.

I know the motor doesn't like it but I have a Hamilton beach scovil milkshake mixer 110 volts running on 220 volts. It makes an awfull noise but it's still okay for a few years now. Still waiting to smell some smoke comming out of it, haha...

Sandy.

Hi Sandy,

The only difference is 100 volts and 10 cycles. Alternating current is the same, phase is usually the same. Your 220v motors usually run ok on one leg of a 3 phase circuit (208v) over here. Our 120v single phase motors may not be built (dielectric strength) to run very well on your 220v.

Art

[CowboyBob]

Steve,

Twinoaks explained it & this is how we always used to setup a 97 years ago since it makes the belt have more contact with the pulley it won't slip as easy.

Bob

[Art]

Hi Sandy,

Remember with the Steinmetz, you implement the capacitance to provide symmetrical voltage at the rotor, but the load must be constant for the value of the capacitor or the voltage will become more and more asymmetrical as the load varies outside design characteristics. The further outside the design the load becomes the more inefficient the motor because of the imbalance in the phases, hence heat goes up too. This is a problem with most motors as they requite significantly more current to start than to run, so you implement two capacitors, one for starting and one for running which is ok if there are only two predictable loads, but that isn't the way it is for the typical motor, so good power distribution is a crapshoot, and the heat generated will cause it's own set of problems.

I generally run three phase motors with a VFD (variable frequency drive) which also gives me the convenience of variable speed, soft start, and good load handling. They are more expensive than the Steinmetz but much more efficient.

Art

Hi Art,

But are you using that running capacitor overthere also? In case of 3 phase motors ofcoarse to run on a 1 phase circuit? Steinmetz circuit? Very few people know about it overhere. Most of them think a 3 phase motor can not run on a one phase cicuit. You will loose a lot of torque, but it's still way enough for sewing.

I know the motor doesn't like it but I have a Hamilton beach scovil milkshake mixer 110 volts running on 220 volts. It makes an awfull noise but it's still okay for a few years now. Still waiting to smell some smoke comming out of it, haha...

Sandy.

[Gregg From Keystone Sewing]

Hi Sandy,

Remember with the Steinmetz, you implement the capacitance to provide symmetrical voltage at the rotor, but the load must be constant for the value of the capacitor or the voltage will become more and more asymmetrical as the load varies outside design characteristics. The further outside the design the load becomes the more inefficient the motor because of the imbalance in the phases, hence heat goes up too. This is a problem with most motors as they requite significantly more current to start than to run, so you implement two capacitors, one for starting and one for running which is ok if there are only two predictable loads, but that isn't the way it is for the typical motor, so good power distribution is a crapshoot, and the heat generated will cause it's own set of problems.

I generally run three phase motors with a VFD (variable frequency drive) which also gives me the convenience of variable speed, soft start, and good load handling. They are more expensive than the Steinmetz but much more efficient.

Art

In other words, make a figure eight out of the belt!@#

On a serious note, good stuff Art, and on point. I know just enough about motors to be able to service them and do what I need to within reason, but it sounds like you know beyond that. Good deal.

[sandyt]

You are so right on that theoratical stuff. Not sure if I understand everything though. Not that technical with electronics.

But in Holland (I guess in Europe) it is very very common to use Steinmetz with clutchmotors. Even sewingmachines comming out of the factory have this. Only a working capacitor. No starter capacitor. Could it be because of the difference 110 volts 60 Hz vs 220 volts 50 Hz??

I even use it with hydraulic pums. Works perfectly without getting anything hot or even warm.

It doesn't work with machines witch need a lot of torque al the time like meat mincers.

If Steinmetz doesn't work, I use a VFD also.

Sandy.