Thread: Is this motor faulty?
-
29-11-2015 #1
Not sure where to post this.
I bought a Becker VT 4.25 Vacuum pump on ebay as it was 'faulty'. This is to 'power' my vacuum table.
I was hoping that it was not really faulty and that I may be able to repair it. I didnt pay much for it, so worth a chance. The machine came without the faceplate but following the manual below, its a 3 phase motor that can be run using single phase. The motor is 0.9KW or around 1.1HP.
http://www.ecovac.com.tw/pdf/rotary_.../oi_vt4.25.pdf
After messing around with starting capacitors, I manage to get the machine to spin up. It runs up to full speed however whenever I add any load, the machine stalls. I found that the wiring wasnt 100%, so I rearrange the wiring. I measure around 6.7 Ohms across 3 distinct coils which seems to imply that the motor is fine.
So, as the motor cannot take much load before it stalls, is it faulty? Could it be too large to run on single phase (Im using a starting cap, no running cap and it stays in circuit all the time, no logic to remove it from the circuit).
Im tempted to buy a 4KW spindle and VFD although I dont strictly need it. The VFD could be used to see if the motor works on 3 Phase. These pumps are expensive and if it works for my vacuum table, it will be a bargain.
Thoughts?
Thanks
-
29-11-2015 #2
If you start the motor without load you need only a running cap, it should be in the range of 35µF. But without running cap, the motor can't run. But you must run the motor in triangle instead of star connection.
Instead that you can use a VFD, but this part is much more expensive.
-
29-11-2015 #3
-
29-11-2015 #4
-
Chaz There is a drawing on the pdf you linked to with a cap does it say the value of the cap? How exactly do you have it connected.
..Clive
The more you know, The better you know, How little you know
-
29-11-2015 #6
-
-
30-11-2015 #8
-
-
30-11-2015 #10
The wiring was a Star connected 6 wire system. That said, when I checked the pattern, it didnt match the drawing in the document, someone could have messed with it.
Ill try delta connection tonight and see if that helps before considering buying a VFD (£120 ish for a 4KW unit that can run the 4KW spindle later).
Thread Information
Users Browsing this Thread
There are currently 1 users browsing this thread. (0 members and 1 guests)
Similar Threads
-
3.0Nm stepper from Zapp stopped working / faulty
By Jonathan in forum Stepper & Servo MotorsReplies: 8Last Post: 10-05-2017, 08:59 PM -
AC servo motor to replace a 3 phase induction motor on a mill spindle.
By rnr107 in forum Spindles & Drive MotorsReplies: 2Last Post: 23-04-2014, 03:14 PM -
servo motor as spindle motor
By Scott in forum General DiscussionReplies: 1Last Post: 03-10-2010, 06:42 PM -
Air compressor - faulty, how do I get the motor out?!
By HankMcSpank in forum General DiscussionReplies: 5Last Post: 26-10-2009, 11:33 AM
Bookmarks