Hi,
I went through pretty much the identical thing on my Wadkin planer. I solved it myself by:
- Opening up the motor and finding the 'star' point
- Breaking into the star point and installing three additional wires(tails) from the star point to take outside of the motor.
- Reconfiguring the motor from 'star' to 'delta'
- Buying a VFD from ebay and wiring the motor directly to the VFD
- Reconfiguring the original DOL to run off of 220v to act as a run/no run signal to the VFD.
It took me a good few hours research to get comfortable with what I was going to attempt, but was not overly difficult once I got my head around the system. It was the technical terms that take time to understand so i'll give you my view.
Motor vs DOL, and Star Point. Below is excerpt from
Wadkin Manual.
- The motor is represented by the three coils on the left, each coil is a winding in the motor.
- The Star point is where three ends of the windings are connected together.
- The DOL (Direct-on-line) is the bit you have been photographing with all the wires attached, and is one the right of the figure. The DOL is basically a switch within a switch. You push the on button and create a circuit through a relay, this closes the main circuit that carries the electricity to the motor. The reason you have this arrangement is so that the full start current for the motor (could be 20+ amps) does not flow through the switch under your finger!
Star (or Y) configuration vs Delta configuration. Drawing below (excuse my art work) shows a representation of the motor. On the left the three windings are joined at the central point (star) and the three leads/wires/tails (green lines) connect to the DOL. In star configuration the star point represents a neutral point and the voltage across the motor becomes 440v (2x220). On the right the motor is in Delta config, and voltage across the windings becomes 220v, again green wires represent the leads to the DOL.
Normally on the outside of the motor you have a junction box, and in this box you join the ends of the winding (a,b,c,d,e,f) in either star or delta configuration, and from this box you take the leads to the DOL. Two pictures below show such a junction box in star (Y) and delta, in star mode (bottom picture) you can see all the ends connected together using copper jumpers.
In your case it look like the tails from inside the motor are just connected together (in whichever configuration) and covered in insulation tape, with wires taken off to the DOL. If you undo these connections you'll be left with six tails exiting your motor, you can then use a multimeter, or a battery and bulb to workout which of the six tails are the start and end of the same winding, ie a-b, c-d, e-f. You can then connect back together in delta configuration (i'd use a terminal block) and take leads off to your VFD.
Using a VFD:
- The VFD has to be connected direct to the motor, you start and stop the motor from the VFD, you do not need a DOL.
- Setting up the VFD is also not that tough but they do have lots of settings and you need to watch a couple of youTube videos, reference the instruction manual (normally written in Chinglish) and get the settings correct.
- The VFD can use an external switch to tell it to run or stop. I rewired the Wadkin DOL, incorporating a £7 relay from ebay, to act as the start/run signal to the VFD. This was a little more involved but meant I retained the original start/stop switch, which i liked.
I really enjoyed learning about three phase motors and getting the system to work for minimum outlay (c.£100), I wanted to try to give you an impression on what was involved as i'd hate you to give up just because you couldn't find the information to understand the problem. Hope some of that helps.
Fitz.
PS. I am not an electrician, I am a DIY enthusiast. Chemical Engineer by background with what I'd say is a good ability to understand technical problems, and reasonable wiring/soldering skills. I understand electrics are very dangerous, the need for isolation, and the risks involved if you wire something up wrongly.