VFD -under volt at source fault

[Gareth Blackstock]

So earlier this year I obtained a large machine with a couple of 3 phase motors in it, and the rest single phase. I bought a VFD, correctly wired it up, and while the machine ran with some functions, it also reported "undervolt at source"

I had bought a VFD with a maximum output of 380 volts. Checking over the machine wiring, I found it had 415volt circuit breakers. However, the biggest draw from the 3 phase motor I found was .75amp. Perhaps I mistakenly believed the 380volt VFD would still run the machine.

So, does the "under volt at source" report on the VFD state I do not have 240volt at the source, or is the VFD indicating I need a higher voltage output VFD? The source is a 15 meter extension lead plugged into the house, the machine is in the shed. Would this distance be enough to lower the voltage at the shed end?

I found a higher rated VFD for sale locally, a 4kw, 6hp, 415volt. Would this be the solution?

Hopefully there are some knowledgable VFD people here?

Thanks, Gareth

 

[Darkwood]

@Gareth Blackstock
Please don't take my post as any kind of attack on your intellect, I made a very good point about these kinds of controls based on your response, IE if it is crucial to maintain a set speed then it may be likely run through a closed looped system, however with the lack of tolerance of the system to speed variations it is hard to give definitive advice, If I actually started to ask you these kinds of questions and you knew the answers I would expect you wouldn't actually need the forums help given your knowledge of such systems.

What made for more confusion and something we try to avoid members doing is multiple threads addressing the same exact issue from the same member, I was not aware of a previous thread until you later posted a link, you yourself have expressed local electricians are not savvy to VSD's and hence my further comment that these systems are more complex and the seeking of help from an electrical engineer who is present on site would be the better options.

Further more and not mentioned in this thread is machine safety and the regulations around that, you are attempting to alter to get a machine running without any real knowledge of the regulations around what you are doing or to that of the codes of practice in the use of VSD's, had I wandered across this thread earlier or your previous one I would have instantly messaged you and advised you get on site hands on guidance by a competent qualified person even if you wanted to do the work yourself, this kind of work shouldn't really be attempted as a DIYer through forum help, again it isn't what you tell us that is the issue, its what you might not realise is important info that could lead to unsafe advice been given.

We are happy for members to help out but we also have to raise concerns when we suspect that someone maybe out of their depth and safety concerns could arise from incorrect advice simply because of the lack of info provided.
No doubt this machine has moving parts, it is crucial that it is safe to use and you are aware of any safety issues that may be present if you got it working and whether its existing safety controls work or even exist.

Whether you respond back is your call but I hope you heed the advice that we normally would not consider this a DIY project that members help on given the inherent concerns of safety and what I will assume is your lack of knowledge of the local machinery control regulations I can only suggest you reflect on what you are attempting lacking such knowledge.