Hi..im new here name is kevin. I was looking over site for information on building a 3 phase convertor and found lots of useful information however...after completion of my 30HP convertor...it wont work !
i have pony motor spinning it to around 3000 rpms...then kick on 240 single phase to it and it is as if you applied the brakes..ive wired it according to the name plate,,,and also in delta and wye configurations,,,getting the same result..and of course wired for the low voltage.....i have within one to 2 seconds turned it off so no damage to windings......windings all check out good and i saw the motor in 3 phase operation before i bought it..
i didnt think it would help to reverse the 240 lines in single phase...but i did...same result......
the unit is not exactly finished as i have no run capacitors install between lines 1 and 3,,,and 2 and 3 yet....intended to install these and level voltages after running...you will note in photo the slotted openings for gauges just above motor in the frame.
well it seems i cannot upload image but...ive made this unit look pretty sharp... but it just doesnt work :idea
3 phase convertor failure
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Rich_Carlstedt
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Re: 3 phase convertor failure
Kevin, Do you have # 4, # 5 and #6 wires tied together and taped off (No Leads !)
Then # 1 and # 7 together and a lead to 220 power
Then # 2 and #8 together and a lead to the other 220 lead
The # 3 and # 9 together and that is your manufactured leg.
Rich
You only need about 1000 RPM..By over driving it instead of 1740 RPM you are causing the windings to reverse the rotation
Slow that pony motor set up down !
Then # 1 and # 7 together and a lead to 220 power
Then # 2 and #8 together and a lead to the other 220 lead
The # 3 and # 9 together and that is your manufactured leg.
Rich
You only need about 1000 RPM..By over driving it instead of 1740 RPM you are causing the windings to reverse the rotation
Slow that pony motor set up down !
Re: 3 phase convertor failure
yes tried that configuration as well...that being a wye connection low voltage....same result how ever motor name plate shows it should be in the delta configuration...is it possible a motor this big is going to have to have the run caps in...even though im already spinnibg with the pony
Re: 3 phase convertor failure
it is a 3450-3600 motor
Re: 3 phase convertor failure
all leads are connected via split lugs and tape
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Rich_Carlstedt
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Re: 3 phase convertor failure
No, Caps are not necessary to allow it to turn, you have a pony motor that does that.
Once a three phase motor is turning and reaches critical speed, it will do so without any external support.
First of all, a 3600 RPM motor is not the most ideal phase convertor to use in my experience.
Second , Many heavier HP motors have two speed start up to reduce high input amps.
I think you may be dealing with that if you are telling me it has wye and delta schematic.
Is it such a motor ?
Rich
Once a three phase motor is turning and reaches critical speed, it will do so without any external support.
First of all, a 3600 RPM motor is not the most ideal phase convertor to use in my experience.
Second , Many heavier HP motors have two speed start up to reduce high input amps.
I think you may be dealing with that if you are telling me it has wye and delta schematic.
Is it such a motor ?
Rich
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Rich_Carlstedt
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- Joined: Sat Dec 21, 2002 12:16 am
- Location: Green Bay Wisconsin USA
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Re: 3 phase convertor failure
You may ask what is critical speed , since it is not the full speed of the motor rating?
It is the speed where the attraction of the next field winding to the armature is greater than the retention
of the previous field. That is the point you need to reach acceleration to normal speed.(RPM)
Some motors do this at lower RPM than others, and thus start easy . The more difficult motors require heavier Caps
to get this going ...on a capacitor start motor.
3600 RPM motors need much higher speeds compared to reach this point.
For instance, a single phase 3600 RPM motor has only two poles and a 1740 has 4 as an example. That means the higher RPM turns half a rotation under the influence of one pole while the other motor only uses 1/4 of the rotation.
Rich
It is the speed where the attraction of the next field winding to the armature is greater than the retention
of the previous field. That is the point you need to reach acceleration to normal speed.(RPM)
Some motors do this at lower RPM than others, and thus start easy . The more difficult motors require heavier Caps
to get this going ...on a capacitor start motor.
3600 RPM motors need much higher speeds compared to reach this point.
For instance, a single phase 3600 RPM motor has only two poles and a 1740 has 4 as an example. That means the higher RPM turns half a rotation under the influence of one pole while the other motor only uses 1/4 of the rotation.
Rich
Re: 3 phase convertor failure
It only has a delta wiring diagram on the name plate. ..however after it didn't work i tried wiring in Wye middle and got the same results
Re: 3 phase convertor failure
Perhaps I'm stupid but "30" hp? Who drives 30 hp from single phase even to the idler motor to produce one leg ? Okay I'm an idiot. Thirty horsepower is way off the chart for me.
I know things have become more efficient but huge cables supplied power as this. To continue my ignorance, you might want to shoot an infrared heat detector at various supply points, during start. There is a squelch factor in wire gage, raising the resistance , which raises the voltage without the amperage to drive it. That higher voltage can burn things without driving them. fjwtss
I know things have become more efficient but huge cables supplied power as this. To continue my ignorance, you might want to shoot an infrared heat detector at various supply points, during start. There is a squelch factor in wire gage, raising the resistance , which raises the voltage without the amperage to drive it. That higher voltage can burn things without driving them. fjwtss
Re: 3 phase convertor failure
Running 4 gauge at 90 amps 10 feet. ..
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Rich_Carlstedt
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Re: 3 phase convertor failure
If it's only a delta, it may be a single voltage (480V ) motor
No way will it run on 240
Rich
How many wires do you have ?
Are they numbered ?
No way will it run on 240
Rich
How many wires do you have ?
Are they numbered ?
Re: 3 phase convertor failure
9 wires numbered 1-9 name plate says 230/460