Phase Converter Question

[bherr]

I recently received a Marathon Electric phase converster with my CNC machine and I noticed it has a low & a high wiring setup. the markings on the motor are as follows:
Model # AD215TTDR7215AA
HP - 5/1.3
Frame = 215T Type=TDR-BE
DES=B PH=B Code=G
2 speed 2WDG Var Torque
RPM =1765/880 Cycle=60
Serial # 990008
Volts=230 Amps = 13.2/5.4
Max. Amp = 40 Duty=Cont.
Shaft = 77507 Off End Bearing =77505
SF= 1.15

So my question is which setup should I use? the CNC is a Bridgeport Interact 412 and has a 7.5HP motor. The guy I bought it from said I would need leveling capacitors. I do I know if I need them and the proper sizes?

thanks in advance
Ben

[tahlinc]

Ben,
Your 7.5 HP Interact CNC will need a minimum of a 10 HP PH converter to operate correctly. Bigger if you can afford it.

Jim

[XYZABisFUN]

Hello Ben,

Jim is correct a 10hp converter would be a minimum.

I had a 5 hp CNC mill (very simular to yours ) in my garage for a time and
I ran a 15HP Rotary converter, had no issues at all.
Now, I am by no means an expert in phase converters or electricity, but this is what I was told and what I've experienced...
Remember that every movement change or spindle on/off it puts a load on the converter. the larger the converter the better it can handle the loads.
(---what I was told---)
I noticed a significant "draw" when I was doing 3 Axis work at a fast pace with lots of direction changes. Spindle on and off while Axis movement also did the same. Also of note here is your incomming power service. (I had a 100 amp line/box just for the machine.)
(---what I experienced---)
Good Luck ,
Will

P.S. I've been told, and read that a "Phase Perfect" Phase converter is the best there is...costs a lot compared to the rotary I have. May be worth checking out.

[afmcorp]

usually hi/low refers to the voltage such as 230 / 460. i've wired up a number of phase converters but never had that hi low issue. mine were always just 230v with a non adjust rpm. the rpm drop is too much for a 60 cyc vs 50 cycle so it appears u can run either rpm. most of the motors would run at 1700 +- rpm.

there seems to be 2 kinds of "rotory" phase conv i've come across. i had a phas-a-matic rotory that the 3rd leg would drop off to 50 volts once the mach motor started and that would kick out my controller [bandit]. then i bought a WGM converter that the 3rd leg stayed at the full volts and that solved the problem. but the WGM had several capacitors already in the unit so alot of words to ask if you are sure the ph conv runs the 3rd continuously.

what i'd suggest is to hook the converter up and use ur vom and see what the voltage is reading and that all 3 legs are active to ground and across leg. i'd start with the high diagram. the lower 800 rpm just seems too low for a 230v set up.

good luck.

[afmcorp]

forgot to mention: because these controllers use the 3ph for just the motor and the rest of the unit is generally just 1ph you need to watch the Kva of the converter. i've got 5 BP boss they run about a total 5kva but the PW with a 12hp motor runs about 23kva if memory serves.

[bherr]

I finally got the phase converter running using a drill to get it up to speed, however I still don't quite understand some things. I hook up 110 to one lead and the other 110 to the second lead. these are not marked so I'm guessing. the third lead I assume is the ground even thought when I measure across these leads none of them show a connection to the motor housing. If I hook up the ground I get a humming noise and it goes away when disconnected. the converter runs on its own when I get it up to speed but the voltages coming off the lead 111,112&113 are very low, about 23.5 volts. what am I doing wrong???????

I was told by the previous owner that this 5HP converter would run the mill, which uswes DC to power the 7.5 HP spindle motor.

Help me PLEASE
Ben

[tonykart91]

What you have is a constant torque 2 speed motor. At high speed 1760 rpm you have 5 hp, on low speed you have 1.3 hp. Connect it on high. The way a phase converter works is, once a 3 phase motor is up to speed it can maintain it's speed on single phase. Using this, it will become a phase generator. It will generate voltage on the third leg equal to the voltage applied to the other two. Line one and two in reality feed straight through to the three phase motor, the third leg is called the manufactured leg and is fed also the the three phase motor. Because two of the legs are powering the three phase motor at ful power, you can use less horsepower converter to run a larger machine. ( Be aware that any electronics must be run off of the non manufactured leg)
That is one principle, I would prefer to use a larger converter if possible but because of the two legs being fed directly you should be OK.

[bherr]

Which leads do I use to hook up the 220v? I have 6 leads, three marked 111,112 & 113. then three other leads not marked. some diaigrams I've seen show hooking the 220 up to leads 1 & 2, which I assume are the 111 & 112.

[tonykart91]

You should have 3 leads marked T11, T12, & T13, instead of 111,112,113. look closer. The other leads should be marked T1, T2 & T3. T11, T12 & T13 are high speed, high horse power. Connect your incoming power to T11 and T12. Run to the 3 phase motor controller with T11,T12 & T13. Make sure that the control circuit is connected at the control with T11 & T12.

[bherr]

Tony,
the T1, T2 & T3 are also labelled 111,112 & 113. the other three wires have no voltage on them at all.

do you know how to calculate the proper size caps to get all the voltages the same?

Ben

[tonykart91]

No I don't, sorry. It depends on the number of turns in the motor windings in relation to the amount of iron in the stator of the motor. These numbers are no obtainable without destroying the motor. If you are close, one or two more of the same capacitor should bring you into tolerances.

[Al_The_Man]

I just posted this link in the other forum look at the FRW files
http://www.metalworking.com/dropbox/...retired_files/
Al.