LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
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- Electrical Contractor
Two wires = single cap.
Chinese motor question
- Thread starter jrjr2u
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
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- Electrical Contractor
Yes, but a cap in series with the entire load doesn't help it start.
synchro
Senior Member
- Location
- Chicago, IL
- Occupation
- EE
Yes. There needs to be two distinct windings, with the capacitor in series with one of them in order to phase shift its current relative to the current in the other winding. To do that, there needs to be at least three leads going to the windings within the motor housing.
- Occupation
- Licensed Electrician
It would be in series with the starting winding.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Right. The OP said it was in L1.
drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
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- Registered Professional Engineer
Are you sure that the green wire is a ground?
jrjr2u
Member
- Location
- Central NY
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- retired
This is the product-The cap assembly may have another internal connection that you cannot see, i.e. this is a PSC motor with the cap outside.
If it is a centrifugal blower, the motor would have to be significantly over sized to be able to handle the added load at 60Hz.
Power requirement on a centrifugal blower increases at the CUBE of the speed change. so at 120% speed (50Hz design getting 60Hz), the power required FROM the motor will be 1.2 x 1.2 x 1.2, or 173% of what the blower needs at 50Hz. So either the 1.5HP motor only needed to be 0.87HP and they almost doubled it for possible use on 60Hz, or the fan is going to require 2.59HP from a motor only rated for 1.5HP and the motor will overload. The fact that the Chinese can't even get the wiring configuration correct leads me to believe this is going to overload.
Good luck with that...
I contacted Vevor technical support and they told me the motor is designed to run on either 60hz 0r 50hz. So there's that for what its worth. The blower came wired with 18ga wire. I will rewire it with 16 for a little headroom (and length) and monitor the amps and temp when I get it running. Might go 14ga if I have some.
jrjr2u
Member
- Location
- Central NY
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- retired
The green wire terminates at a screw attached to the motor frame. It's actually a yellow/green wire
- Occupation
- Licensed Electrician
There would be some extra connections inside the motor housing like the diagram jraef posted.
jrjr2u
Member
- Location
- Central NY
- Occupation
- retired
The easiest way to think of voltages in the rest of the world is like the common US 480Y277, in the old days we had 440Y254, now instead of notching up 40 volts to 480 everyone else notched down 40 volts to 400 so they have 400Y230 the motors are rated for voltage drop (220).
- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
Just because the motor can take 50/60Hz, doesn’t change the physics issue of the effect of running the blower at 120% speed. I have dealt with people getting “technical support” from Vevor a few times in the past couple of years now, they don’t know squat. They are at best, IMHO, just mouthpieces for the Chinese to try to avoid having their stuff sent back.
jrjr2u
Member
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- Central NY
- Occupation
- retired
Much the same as all the other Chinese 'Technical support'. That's why I said - for what that's worth! I will see how much magic smoke gets released. If none, at least this is not something that will run unattended. I will be keeping an eye on it.
Seems like it may be a UK version with the 50 Hz and the green/yellow earth wire.
jrjr2u
Member
- Location
- Central NY
- Occupation
- retired
Very well could be. I hope it works out ok as I probably wouldn't buy another motor if it smokes. The weather is starting to warm up here so this next week I will probably try it out. I have to install a 220v outlet first.
drcampbell
Senior Member
- Location
- The Motor City, Michigan USA
- Occupation
- Registered Professional Engineer
It will be a crapshoot. Turning a fan at 120% of its design speed will require almost (120%)3 the design power and (120%)2 of the design torque, which will result in approximately (120%)2 of the design current and ((120%)2)2 of the design I2R heating. It will probably "work", but it's not a recipe for longevity.
The little bit of good news: You don't need to worry about starting torque. Fans don't move much air -- and don't need the motor to supply much driving torque -- near zero revs/minute.
jrjr2u
Member
- Location
- Central NY
- Occupation
- retired
Not sure how much 'design' there actually was! It's more like throwing together a bunch of stuff together and getting it on the market.
Caveat Emptor
kwired
Electron manager
- Location
- NE Nebraska
From what I have seen so far in this thread, it is probably a PSC motor, 2800 RPM @ 50hz would mean it is a 2 pole motor. Running it at 60 Hz would make it run about 3400 RPM. If this is running a blower, hopefully it was oversized to begin with so that it can work on 60 Hz without overloading in short time. Still have to question the expected longevity of the design though. On top of that if it came with 18 AWG cord, that is getting kind of marginal sized for what says is a 1.5 HP motor at 50Hz, it will draw even more if operated at 60Hz.
Connections diagrams shown so far (from manufacturer) are sketchy, pun intended. Drawings others have posted on how a PCS motor is connected is likely how this motor is actually connected, but they are only schematically/fundamentally accurate and may not have every detail this actual unit has within it.
And to the OP - most countries that utilize 50 Hz distribution have nominal systems of 415/240 volts wye. 415 volts phase to phase and 240 phase to neutral. Most the single phase equipment they utilize runs on that 240 line to neutral. In more remote areas or at dwellings they might just have 240 single phase, but it is one hot and one grounded conductor there is not 120/240 like there is in North America
Connections diagrams shown so far (from manufacturer) are sketchy, pun intended. Drawings others have posted on how a PCS motor is connected is likely how this motor is actually connected, but they are only schematically/fundamentally accurate and may not have every detail this actual unit has within it.
And to the OP - most countries that utilize 50 Hz distribution have nominal systems of 415/240 volts wye. 415 volts phase to phase and 240 phase to neutral. Most the single phase equipment they utilize runs on that 240 line to neutral. In more remote areas or at dwellings they might just have 240 single phase, but it is one hot and one grounded conductor there is not 120/240 like there is in North America
Thats interesting I am no motor expert, so here is a dumb question; An old timer once told me something about a magic ratio of 8? volts/hertz . We had a German or Italian motor rated 400V 50HZ and I think the old timer changed something simple to make it 480V 60 hz, so since the OP's motor would be runing at 240 and not 220 would that factor in at all?
This was way back in the 90's before VFD's were so common.
- Occupation
- Licensed Electrician
The volts to hertz ratio for 400V 50Hz is the same as 480V 60Hz -8- so your motor would run on either power system with no changes to the motor. The only thing I can think of that he would have changed is the configuration of leads to accommodate a supply Voltage of 240V or 480V.
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