Thanks: 0
Needs Pictures: 0
Picture(s) thanks: 0
Results 46 to 60 of 146
Thread: Clarifying 3ph Motor connections
-
28th Dec 2013, 10:32 AM #46
Hi Dean,
I think I have a solution that will work with what you currently have. That picture of the terminal cover jogged a few brain cells...
You have a Delta, DoubleY Dahlander. Which can be converted to 240V 3Ph double delta. ( some other Dahlander configurations require rewinding the motor! ) by Linking U1 to U2, V1 to V2 and W1 to W2.
AM_Dahlander.jpg
You can then run at 4 pole (1440 rpm) fulll power, ( or as much as your VFD can deliver ).
What you will find is that even though it's full load current is going to be 25A or so, most of the time in normal operation you will be drawing a lot less than that.
So If you program the current limit on the VFD to suit your power cabling, I'd guess 15A? then you'll get 4.5-5 hp, see how that goes with the machining you'll be doing before you go looking for a bigger VFD.
Regards
Ray
-
28th Dec 2013, 11:47 AM #47
Gallegos.
I would say the vfd you have will be fine if you are happy to limit the power and have a longish start ramp time. I would definitely recommend an ammeter on the supply to the vfd so you know whats happening... I have a combined ammeter voltmeter that was less than 10 bucks on ebay but seems to work great.
If I find the VFD too limiting then I can upgrade it later. I can always use this one on the shaper.
An ammeter is a great idea.
Is the motor you converted for your mill similar to mine or a single speed motor? You are saying to cut at 2U, 2V, 2W?
Motor Winding Circuit.jpg
I would be interested in looking at books on this subject. Thanks.
BaronJ.
This motor is original for this lathe. 2 speeds to get full range of speeds for the lathe. Slow speed up to 1000rpm and high up to 2000rpm. Saves doubling up on the gearing.
BobL was only looking for a picture of my cover. Waiting very patiently I might add.
Keith_W.
PDF is very useful.
PDW.
I know a bloke in Donald that might be able to help you out if you want to go that far. PM me for his details, he looks after the electrical stuff etc for a couple factories and I'm pretty sure he has some motors lying around as spares, might have a 5 HP unit. Very nice man to deal with and a wealth of information. Also I may be interested in buying that motor off of you if you can't use it yourself......
Dean
-
28th Dec 2013, 12:00 PM #48
Ray.
I will do this first. Thanks for this info. I have decided to try and jog my brain cells and read up on these motor some more if I get some books off Gallegos or find some myself.
A quick check with an online calculator tells me that 6mm2 cable is capable of up to 41A. 30deg average temp, 45m run, 5% loss. I think I will put in a 32A breaker. That should cover it.
Dean
-
28th Dec 2013, 12:11 PM #49Senior Member
- Join Date
- Aug 2009
- Location
- Quindanning, WA
- Posts
- 175
Yeah... If you only have 6 leads coming from the motor into the terminal box you will find one of the leads will go to each of these points Inside the motor and split. If you are going to open it up and modify it i would put in individual leads for each coil group so you have 12 leads to the terminal box. If you do that you will be able to choose to have it as either 4 or 8 poles by changing polarity on 3 of the coil groups. The motor will be 7.5 hp either way once its parallel delta.
Whats the vfd current rating? I would try to limit current on the single phase side to the rating so the bridge rectifier isn' t stressed.
My mill motor was a 4 pole single speed but i also did the same to the 3 hp power feed motor and i reckon yours could potentially be easier because the windings are already split.
I will have a look for the books.
-
28th Dec 2013, 12:32 PM #50
-
28th Dec 2013, 12:56 PM #51
I thought I would have a quick look on EvilBay as It is a long time since I have checked VFD's. The following is a link to a 5.5kW (7HP) single to 3 ph which has a remote control unit supplied with a 1m cable. It seems to be a standard network cable so can be changed for any length required. This VFD is $825 +$25.
Dean
-
28th Dec 2013, 01:37 PM #52Hugh
Enough is enough, more than enough is too much.
-
28th Dec 2013, 04:35 PM #53
That's ok Hugh. That part of your drawing (2 speed) was the same as the one linked (PM) in a previous thread by Simon except the coil layout was different. Same end result. Same connections. I compared them and used the one from PM as it was clearer. I have another confession to make. I looked for the same diagram on Google as your single speed one so I could see it clearer. Thanks for the diagrams as they were helpful to point me to others.
Dean
-
28th Dec 2013, 04:50 PM #54Senior Member
- Join Date
- Aug 2009
- Location
- Quindanning, WA
- Posts
- 175
This is the vfd im running
Variable Frequency Drive Inverter VFD 7 5KW 10HP 34A | eBay
And the ammeter
Blue Digital Voltmeter Ammeter AMP Current Volt Voltage Meter Panel 300V 50A | eBay
-
28th Dec 2013, 05:22 PM #55
Last edited by Oldneweng; 28th Dec 2013 at 05:35 PM. Reason: Notebook Keyboard Playing Up
-
28th Dec 2013, 05:55 PM #56Member: Blue and white apron brigade
- Join Date
- Feb 2006
- Location
- Perth
- Posts
- 7,183
I've used 4 of those AC ammeters.
I have two extension cords with them built in and the others are on machines.
This one is on my DC
-
29th Dec 2013, 01:13 AM #57Golden Member
- Join Date
- Jun 2005
- Location
- Helensburgh
- Posts
- 618
If you are ever tempted or have the opportunity to use three phase from a generator make sure everything is wired correctly. I had a customer who did not wire things correctly and it cost him a motor rewind. Apparently just plugging it in can lead to problems as his pocket found out.
CHRIS
-
29th Dec 2013, 09:47 AM #58
Now that would be a job for the experts. We had a pump at work that was attached to a frame with wheels, made by an apprentice we called psycho and so the pump was named psycho. It was a slow pump until some years later it was discovered that the sparky had connected it to run in reverse. It gets used more now. We use pumps that we push to the job.
Dean
-
29th Dec 2013, 09:54 AM #59Hugh
Enough is enough, more than enough is too much.
-
29th Dec 2013, 10:21 AM #60Senior Member
- Join Date
- Aug 2009
- Location
- Quindanning, WA
- Posts
- 175
Cant remember the size of the hole in the ammeter... They used to be slightly different with a smaller toroid attached to the back but it still it fit a 6mm2 cable comfortably. You only need to run one wire through the toroid, dont think it matters if its active or neutral.