115V To 230V Motor Wiring - Smoked 2 Motors, Learn From My Mistakes...

BladesIIB

BladesIIB

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Converting a single phase motor from 115V to 230V should not be that hard, and yet I managed to smoke not 1 but 2 brand new motors. 90 seconds of run time each on these 3/4HP Permanent Split Capacitor (PSC) grinder motors. Wanted to share how I did this to hopefully prevent someone else from making the same mistake. I got to wrapped up in the instructions that said you don't have to move any wires, instead of really focusing on and fully understanding the wiring diagram. When there are jumpers involved, wires can go in different places and the factory does not always put them where they say they did. Check out the video for the full story wiring this Grizzly 5963 surface grinder, and I really hope this saves you some time, money and energy.

 
Back in the day I helped wire up dozens of small to large motors at a factory. The practice was to "bump" the motors to avoid smoke and to check the direction of rotation. Usually, the bump would be for just a second or so, a quick "on-off". Then, once we got the direction right we measured currents a few seconds at a time. Bump, measure, off. Repeat for three phases. This way, we found any miswiring issues. Some of these beasts were 500 HP or more. Some of the equipment didn't react well to incorrect rotation and smoking a $$$ motor was frowned upon. I still "bump" equipment to this day as it has saved my bacon from my own mistakes more than once.
 
Reddinr said:
Back in the day I helped wire up dozens of small to large motors at a factory. The practice was to "bump" the motors to avoid smoke and to check the direction of rotation. Usually, the bump would be for just a second or so, a quick "on-off". Then, once we got the direction right we measured currents a few seconds at a time. Bump, measure, off. Repeat for three phases. This way, we found any miswiring issues. Some of these beasts were 500 HP or more. Some of the equipment didn't react well to incorrect rotation and smoking a $$$ motor was frowned upon. I still "bump" equipment to this day as it has saved my bacon from my own mistakes more than once.
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Good tips for sure. I was definitely guilty of having to much confidence in my abilities and thinking this was “so easy” from the instructions what could go wrong. I feel sufficiently humbled now and will apply some good testing steps in the future.
 
Understanding the instructions is very important. We had a customer a number of years ago that was rebuilding a centrifuge, called up to order a spindle and set of bearings. At the time I think it was $7-8,000 for them. A week later calls again for another set. A week after that calls again for a third set. This company only had two machines and this was the last spindle in North America. My boss asks why they keep buying these parts, customer says the bearings keep failing and wiping out the spindle. Turns out they were putting the angular contact bearings in upside down due to flipping the spindle upside down to install, but not the bearings. Now that was an expensive mistake!
 
Ischgl99 said:
Understanding the instructions is very important. We had a customer a number of years ago that was rebuilding a centrifuge, called up to order a spindle and set of bearings. At the time I think it was $7-8,000 for them. A week later calls again for another set. A week after that calls again for a third set. This company only had two machines and this was the last spindle in North America. My boss asks why they keep buying these parts, customer says the bearings keep failing and wiping out the spindle. Turns out they were putting the angular contact bearings in upside down due to flipping the spindle upside down to install, but not the bearings. Now that was an expensive mistake!
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Yes for sure. Thankfully my stupid tax on this one was not near that high! Ouch…
 
BladesIIB said:
Good tips for sure. I was definitely guilty of having to much confidence in my abilities and thinking this was “so easy” from the instructions what could go wrong. I feel sufficiently humbled now and will apply some good testing steps in the future.
Click to expand...
I have made pigtails with auto fuses (blade type using crimped connectors) to protect the motors. I haven't had one blow, but if I get it wrong, I hope the fuse will blow.
 
Reddinr said:
Back in the day I helped wire up dozens of small to large motors at a factory. The practice was to "bump" the motors to avoid smoke and to check the direction of rotation. Usually, the bump would be for just a second or so, a quick "on-off". Then, once we got the direction right we measured currents a few seconds at a time. Bump, measure, off. Repeat for three phases. This way, we found any miswiring issues. Some of these beasts were 500 HP or more. Some of the equipment didn't react well to incorrect rotation and smoking a $$$ motor was frowned upon. I still "bump" equipment to this day as it has saved my bacon from my own mistakes more than once.
Click to expand...
We used the same practices when building and installing machinery. The boss isn't very happy if a 500 hp motor goes up in smoke or destroys a multi-million-dollar production line because it's turning the wrong direction
 
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