It looks like, from your picture of the motor, that there is a pulley on the motor, so that means there needs to be a belt also. Are you sure that the belt is put on correctly? Some machines with a Vbelt use a 'half twist' to reverse the final drive direction.

Also is this motor original to the machine, or is it a "refit", a different motor being put on the machine? I ask because you mentioned, "There is no other orientation that I can figure out to turn the motor 180 degrees to "mechanically" solve the issue."

Half twist! Very interesting. I think the length of the vbelt prevents the use of a twist? Would friction not be another issue with a twist?
This is the original motor. Not a refit.

 

Is this a 880D1 model? If so it shows the actual motor direction as CCW when looking into the end of the shaft. Is this how the motor is rotating on yours?
Max.

 

There was no "rewiring" with the rebuild. The motor can not be installed in any other orientation... Hummm... I am sure there is an easy answer - just not coming to me...

In the rebuild was the belt replaced? If so maybe the wrong size belt was put back on. The half twist as shortbus mentioned would fit this scenario.

 

Could the original poster post a picture of the specification plate from the motor?

 

Half twist! Very interesting.

The half twist as shortbus mentioned would fit this scenario.

Some small machines at one place I worked did this. Also a very old snowblower I had used two different belts to drive the wheels, one like normal for forward, one with the twist for reverse. Depending on which one was tightened by an idler pulley the direction was changed.

 

Try reversing the conductors from wall outlet to transformer. If you have a polarity sensitive transformer you might be getting a reversed polarity on the DC that is rectified for the machine's motor.

Many transformers are "polarity sensitive" in that their plug must be plugged in the right way. In theory, transformers should be properly designed so that polarity is not important. In practice, this has not been the case. With many transformers, if you plug them in backward then the 110 volt outlet is actually 220 volts on one pole and 110 volts on the other. It looks like 110 volts to the appliance (220 minus 110), but the appliance is floating 110 volts about ground. This is dangerous because you can easily get shocked by touching any exposed metal or touching it with sweaty or otherwise wet hands. If it's a fax machine, then you may burn it out when you plug in the phone line which gives a ground.

Check the two 110v output legs against ground (earth) with a volt meter, if one leg is 220 and the other is 110 reverse the transdormer's supply leads at the wall plug. If the transformer is plugged in correctly, then you should get zero or neutral (maybe a few volts) on one outlet pole and 110 volts on the other pole. This is no joke. We live in Thailand, have a 1500 volt amp transformer made in Germany, a 500 volt amp transformer made in China, and a 500 watt transformer from the USA thet are all polarity sensitive.

If you have two prong wall sockets (no ground) you should make sure that if the transformer is unplugged, then when it gets plugged in again by whoever touches the plug, it's polarity is correct in the wall outlet. One way is to mark the wall socket and the plug with a marker or long-lasting sticker, e.g., Left to Left and Right to Right for a horizontal plug (two L's or two R's), or Top and Bottom for a vertical one (T-T or B-B). Most USA wall sockets have a wide prong and a slightly narrower prong so that polarity sensitive plugs can fit in only a particular way. Of course, this assumes that whoever installed your wall sockets installed them properly which is very often not the case -- i.e., the wider prong is supposed to be neutral, but it is often erroneously the live wire.

A wall socket polarity tester is a handy little tool at about US $5.00 to check that your wall outlets (power points) are wired properly. One of those little screw drivers with a neon bulb in the handle will tell you which side is hot. When looking at a wall socket with ground hole at bottom the right hand side shoud be hot, left side nuetral.

 

Try reversing the conductors from wall outlet to transformer. If you have a polarity sensitive transformer you might be getting a reversed polarity on the DC that is rectified for the machine's motor.

Ah, no. AC "polarity"will not alter the DC polarity.

Many transformers are "polarity sensitive" in that their plug must be plugged in the right way. In theory, transformers should be properly designed so that polarity is not important. In practice, this has not been the case. With many transformers, if you plug them in backward then the 110 volt outlet is actually 220 volts on one pole and 110 volts on the other. It looks like 110 volts to the appliance (220 minus 110), but the appliance is floating 110 volts about ground. This is dangerous because you can easily get shocked by touching any exposed metal or touching it with sweaty or otherwise wet hands. If it's a fax machine, then you may burn it out when you plug in the phone line which gives a ground.

I take it you are referring to auto-transformers. Connecting a 110V to 220V auto-transformer each way can give you 220V "above" neutral, or 110V "above" and 110V "below" neutral. And as the neutral is connected to earth at the switchboard (at least in Australia), it is then referenced to earth. But no power connections in the appliance should be connected to earth, or the case, so it should not be a problem. If it is, there is a fault on the appliance. There my be some capacitive coupling, but that should be fairly high impedance.

 

It may be that there is a lot more than is obvious. Some universal motors have an internal means to change the rotation, and some controllers output a voltage that is pulsating DC. And some motors have brushes and a permanent magnet field. Those motors are polarity sensitive.
So the first thing to do is to get a meter and check voltages and see if perhaps some polarity was reversed someplace. And I doubt very much that it is a BLDC (Brushless DC) motor, because ALL of them require an electronics package to drive, either internal or external.

BUT WAIT!! You stated that the motor is under MCU control. Where is the MCU in the circuit? I am guessing that the MCU, wherever it is, controls the speed of the motor.
Please let us know how they all hook up, because something does not sound quite right.

 

In reference to polarity sensitive transformers. I also have a small 60 watt travel transformer, name ‘Newstar’ bought in Australia. It has two round European style pins so can be plugged in either way. It has the characteristic of being correct if plugged in in one direction but if turned around so it is plugged in with the pins reversed the output socket becomes 220v to earth on left side and earth to right is 110v but voltage across the two is 110v, as described in my earlier post.

I have a 110v hair clipper that I use with it - motor type, not vibrator type. If the transformer is plugged into a power point backward there is 220v between clipper teeth to earth when the clipper is turned off. But no voltage between the teeth and earth if the clipper is turned on.

If anyone here does have a household step up/down transformer it would be interesting to have their theories after actually doing some tests with a volt meter. There must be simple step up/down household transformers that are not polarity sensitive but that is not the case with any of ours.

Also interesting is that our 500 volt amp Chinese transformer having three output power points, 3 prong type, has one of them wired correctly, neutral laft / line right, but the other two are wired backward. When buying equipment or moving into a new house its beneficial to check things out with your own meter

 

It sounds like it is an auto transformer. But the the measurement to earth is really irreverent as no mains power circuitry in your device plugged into it should reference earth anyway.
And I think "polarity" is really the wrong term to use. That is normally for DC.
This is what I'm referring to....

In both cases, the output is still 110VAC.

Is that what you are finding?

 

Right - you make it easy. Thanx. The symptoms spell auto-transformers. Plus they are most likely auto-transformers as that is the cheapest type to make and sell. It would be nice if small dual winding isolation transformers were more available.

True enuf - polarity is more correctly a D.C. term. But also what can be the term when referencing earth to line..?

 

Polarity certainly can matter in AC power circuits. But I am talking about phase polarity. At least in most of the USA we have two opposing phases delivered to the house, which allows 240 volt appliances to be operated by using both, while 120 volt appliances are fed between one side and the neutral point, which is supposed to be at "ground " potential. Usually this works quite well, and it certainly reduces the severity of electrical shocks, which are still dangerous. It also reduces the amount of copper needed for wiring, which is handy.
I am not sure how that is handled in the areas where the main outlet voltage is 220 volts. For the machines that we sold in countries with 220 volt systems we always had a transformer at the power inlet that stepped the voltages down to what the application required, and we used motors rated for that area's power supply voltage. And the transformers provided ground isolation very well, since we never used auto-transformers.
In this case, with the motor running in the opposite direction, it seems more likely that something has been changed that was not understood.

 

What is the model number of the Gemsy?
A photo of the machine and how the motor is attached would be useful.

This is a Gemsy 8800D

 

But I am talking about phase polarity. At least in most of the USA we have two opposing phases delivered to the house, which allows 240 volt appliances to be operated by using both,

To infer a N.A. domestic supply service 2 phase is a misnomer, it is simply 1 phase derived via a single phase primary with a 1 phase C.T. secondary, single phase transformer.
A two phase supply is quite different.
Max.

 

I trust people realize this thread had ended a bit less than a year ago.

 

I trust people realize this thread had ended a bit less than a year ago.

But how did it turn out? Please don't leave me hanging.
I suspect it is related to #4 in post 15. The motor was turning in the right direction but was mounted wrong.

 

I trust people realize this thread had ended a bit less than a year ago.

OMG!
I got caught up in the stream.

 

It's easy to get snagged into these old threads that someone resurrects.

I'm with Yli - I'd like to know how it turned out, since the original problem is one of those "Huh? That makes no sense whatever" situations.

 

I suggest that the folks operating this really great site consider adding the start date of a thread in a fairly large font at the beginning. I have followed threads a a ways and then got a note: "This thread is 3 years old, do you still want to respond?" I had no clue it was old.. It was listed with new ones.