|Forum topic by NormanW||posted 09-23-2014 09:52 AM||1620 views||0 times favorited||9 replies|
09-23-2014 09:52 AM
Wiring on a Chinese motor
I wonder if someone with intimate knowledge of 220V AC motor wiring can help me with a problem?
I purchased a new multi purpose woodworking machine for making mortice and tennon joints and planing timber. The machine was made in China and came from India. There is no manual although with the exception of the wiring, it is extremely robust and appears well made. Built by blacksmiths comes to mind. I have not received any assistance from the supplier, so have to figure this out on my own.
When it arrived I checked it over and found that there was just a two pin plug, no earth, with 1.5mm copper cable in a blue and a brown sheath. This looked like lighting cable and for a 2HP motor seemed inadequate.
When I looked inside the plastic peckerhead cover on the motor there are six leads, two red leads and two yellow leads that go into the motor through two different holes in pairs, and two yellow leads that go to the capacitor. Connecting the switch to the motor were four leads, two blue and two green and yellow (earth cable), and a green and yellow earth lead that was not connected to anything. There is no wiring diagram. The wiring was not well done with stray copper wire ends coming from connectors and the colours were all wrong as well.
I didn’t try the motor in this configuration. Rather, with a circuit tester I traced which wire went where, then put in a new 5 core 2.5mm cable, brown, blue, black, grey and earth from this block to the switch (and a 3 core power lead to the mains). Brown is live (one of the original blue wires), blue is return and the grey and black replace the two green/yellow leads that were present. This is as wired now.
I have taken digital photographs all along, and those below are of the original wiring configuration. In the absence of any connector identification, I have added the numbers and letters to help make sense of it.
When I turn the switch on, I get loud buzzing from the motor, but no movement. I only try it for a second or two and it doesn’t trip the RCD. The motor turns freely by hand. The switch has three buttons, green, black and red. Red returns a depressed button to off, but I suspect having drawn a circuit diagram of the wire pathways when a button is depressed that the motor direction is reversed by the black button.
At the switch there are the two wires in from the mains. There are permanent links between the mains lead connectors and the three cables from the centre connectors. The fourth cable to the peckerhead block is direct from the incoming power, so which ever button, black, or green, is pressed, power also always goes to terminal 6. This means that even when no buttons are depressed, there is a live lead at the motor which to me is dangerous.
I have replicated exactly the wiring I found, only with an earth, and normal coloured cables, but clearly something is wrong.
Dismantling the switch, there are connectors from each button which join the outer three terminals on each side with the centre three terminals, so the key appears to be where the wires lead from these centre three.
I took the capacitor out of its covering. There are two unmarked terminals at the top. In the photograph, the right lead (I call X) goes to terminal 3 on the peckarhead block. The left terminal (I have called Z) connects to terminal 5. I do not know enough about the function of the capacitor to understand what, if anything, this means. There are no leaks from it and the plastic shrink wrap seal is in good condition.
Removing the Capacitor, after discharging any residual voltage, I checked it with an analogue multi meter. Connecting the + probe to two different wires gives differing results. With ’+’ connected to wire X and ’-’ to Z, and the meter at X1K Ohms the needle immediately deflects to the end of the scale then settles back. At a second test the needle deflects 1/3 across the scale and settles back. I think this means the capacitor is OK. The capacitor is marked as 220/240 V AC, 300uF Q .
This leaves then the wiring setup at the motor. As I said at the start, I don’t know enough to know whether it is right or not. I would question whether having power always coming to terminal 6 on the peckarhead block is normal? This is a wiring layout, with original coloured wires, green button depressed.
I have tried to locate a company website but failed and although I have the machine name and number, there is nothing on the internet for it. I suspect it was manufactured some time ago, although everything was wrapped in brown wax paper, protected and greased, it just looks so 1960’s. There is a date on the engine plate of 1993.
Thanks for reading and apologies for the length, but I wanted to try and explain as muach as I could in one go. Any help would be appreciated.