Is this a 3 Phase Static Converter?

[raross61]

Gents; The "N" series AB heater is just the heater portion only. If you step up you may also use the "W" series heater which has the heater and aforementioned solder spindle included. To use the "W" series remove the existing solder spindle by removing the two small screws under the heater on the overload block. The spindle is spring loaded so will jump out at you when you loosen the second screw. Relax, this is normal! Throw the old solder pot and two screws away and insert the new heater with the two original large screws. Now push the reset button/bar and the unit will be good to go.

Both series of heaters are wound with the same size nichrome wire so the numbers on the heater remain the same. Check the motor name plate, the consult the heater chart and get the heater that as close as possible matches the amp draw of the motor. Do not oversize. Heaters are already sized to allow a twenty five percent overload without tripping. Remember this is a slow operation. The motor must remain in an overload condition for a period of time before tripping. This allows time for the heat to build up in the motor and temporary overload conditions to cure themselves. The fuses/breaker ahead of the starter are there for the instantaneous disruption of power should a serious overload or short circuit or ground take place. A oversized heater will allow the motor to cook and basically provides no protection at all. Insulation break down caused by excessive heat is what this is all about. The reason motors burn out.

By the way, the starter you have is indeed an oldie but a goodie. Should anything happen to it you may have trouble getting repair parts. I would plan on scrapping it when the time comes and replacing with something produced in the 20th or 21st century. Just a thought.

HTH

Just wanted to personally say Thanks, for the heads up on the two heater style overload system! Never came across one of these, before! I do see where it would work perfect, in the normal 3 phase delta setup, but like you said when one leg grounds, to the case, and especially the leg with no heater! Now that's another story! IE=BAD

Take Care Bob in Oregon

 

[raross61]

I ordered a clamp on multi meter.
I also ordered new in shelf worn boxes N33 and N38 for next to nothing on Ebay.
Both are enroute.
Please anticipate that I may attempt to provoke you into coaching me further when they arrive.

Thank you,
Daryl
MN

Hi Daryl,

Just wondering did you get your new meter yet? I was just dying to know, if you got your meter? And is the Gisholt going again?

Bob in Oregon

 

[Uglydog]

Hi Daryl,

Just wondering did you get your new meter yet? I was just dying to know, if you got your meter? And is the Gisholt going again?

Bob in Oregon

Thanks for following up!
The Amprobe ACD-14 clamp-on arrived today (7/30).
I'll do some reading tonight, with a hope of growing some confidence on how to use it.
It's on my list of things I want to complete before we leave to visit TOAG in Ohio.
Likely I'll start a new thread so that anyone searching for how to balance 3phase legs can find it.

Whadaya think? Is that a good idea?


Daryl
MN

 

[Uglydog]

Disclaimer: only a licensed electrician should do this!
EVER!!

Results:
Test #1
Avg .0404, Max Deviation .2696
Line A / Leg 1 .043
Line B / Leg 3 .31
Line C / Leg 2 .011

Test #2
Avg .0516, Max Deviation .0056
Line A / Leg 3 .0216
Line B / Leg 2 .079
Line C / Leg 1 .023

Test #3
Avg .0656, Max Deviation .0106
Line A / Leg 2 .0164
Line B / Leg 1 .0106
Line C / Leg 3 .0056

Looks like Power Source Line C is the problem and not the motor.
Most likely the used (CL) Rotary Phase Converter.
Hmmmm.
Do in line fuses (not circuit breakers) get weak? Or are they always on/off, work don't work?
Fortunately, the manufacture of the Rotary is a local small electrical company with a good reputation. However, it won't be under any kind of warranty.
The current configuration (Test #1) has the worst results!
Think I'll wire her in the Test #2 configuration with a Thermal N33 and see what happens.

Any observations or corrections?
I really don't know what I'm doing and sincerely appreciate all of your input and feedback!!

Daryl
MN

 

[rdhem2]

Are we assuming the motor is running? Seems like not, but than you should have no reading what so ever. Amprobes usually have a six amp scale. Turn down to that and see what you get. Usually a motor idling along with no load will draw from about 1/3 to 1/2 the name plate rating. If you mentioned the full load nameplate rating I missed it. Just clamp the jaws around the wire going to one of the motor leads. If the reading is small wrap the wire around the jaw several times then divide the reading by the number of wraps.

Unless you are experiencing nuisance tripping of the overloads or the readings are really unbalanced, like 30 to 40% or more phase to phase don't worry about it. You are going to get goofy readings anyway with that phase doohickey thing you are using trying to invent the third leg.

Good luck, keep us posted.

 

[Uglydog]

Finally got back out to the shop!
Ran the Gisholt for 3 hours straight boring 1/8" black pipe... really slow.
Needed a sleeve. Wish I'd have had some different scrap.
No problems with the Gisholt whatsoever!
Really hot ambient temperature, and all the houses have their ACs on. Just in case it might have been power company issue.

Looks like changing some wires around and seeking improved balance made all the difference.

Thank you all for being patient with me as I expand my marginal electrical knowledge!!!

Daryl
MN

 

[Ulma Doctor]

Hey Daryl, i'm glad to here everything's running well...
If you are interested i can help you get your RPC easily within 5% balance if you are so inclined.
The third leg is generated by induction, there really is no magic happening inside your RPC.

Contrary to popular belief it is quite easy to balance even a 25 hp RPC, if you know a couple things before you start.

If you are interested send me a PM, i'll get you dialed right in.
i'm happy to help out anytime...

mike)