Quote Originally Posted by m_c View Post
It may be down to how each machine is connected. Do you have this machine connected, so the two legs (2 & 3) that power the control circuits, are connected to the non-generated leg on the converter?
I will find the Transwave manual and have a look, do you mean L2 and L3 on the drawing?

Quote Originally Posted by m_c View Post

With most common single to three phase converters, two legs are supplied directly from a step-up transformer, then the 3rd leg is generated using purely capacitors (in the case of static converters), or by a combination of idler motor and capacitors (in the case of rotary converters).
If you connect one of the control legs to the generated leg, then it is very likely to sag under motor starting loads, which would explain your symptoms. If you have had it connected this way, then there is a possibility that converter is the problem, which is why we're asking about voltages. It could be the converter has either developed a fault (some will try and boost the voltage under high load conditions), or it could just be a combination of capacitors getting a bit weaker as they age, a bit extra load on the motors, and the cold weather making things a bit sluggish, that have pushed things to the point the problem has become apparent.

And if your other machines are connected so their control circuits are powered from the non-generated legs, it would give the impression the convertor is working fine, as although the generate leg would sag while starting, you probably would not notice any difference unless really pushing the machines to their maximum loads.

So in short, check what voltages you're getting into the control, especially the voltage at the transformer that is supplying the 230V for the controls.
So using test meter on Hv setting I get 237v on a workshop socket outlet (just checking I'v got the correct range) then 160v over the low side of the transformer and 364v over the high
side. 160v seems too low?

The contacts made well some times and chatterd others. Going to look for manual for Transwave.