Thicknesser electrical problem, help needed!!

[MikeK]

I hope Roy and I don't cross paths with suggestions, but after reading the online operator's manual for the FS 30 Elite, I was wrong about the rotary switch and the auxiliary start/stop contacts. The rotary switch is the thermal overload protection, but the controls to turn on and off the machine are on the side panel. If I understand the manual, you turn on the machine by pressing the white button and turn off the machine by engaging the emergency stop button.

There appears to be something wrong with your machine if the start button (Item C in the illustration below) is illuminating as soon as you rotate the switch (Item B in the illustration below). The light in the start button should only illuminate when the button is pushed and the machine is running. The light on the side panel (Item D in the illustration below) should illuminate as soon as you turn the switch.

I've never seen the motor brake release selector (Item E in the illustration below), so this is new territory for me. It is not identified in the electrical schematic. However, it is interesting that the manual states the motor brake releases 20 seconds after activation of the selector switch and you are observing the motor stopping after 20 seconds. Are you sure the brake release switch is in the correct position?

Below is an annotated section from the electrical schematic showing the components identified above.

 

[Spectric]

The transformer is set to put out 110v

Yes that is it's designed output but with a 400 volt input, if you only have one side connected then you will not have 400 volts present so the output would be lower.

This is progress, what this is saying is that there is enough power for the light but not enough to operate the contactor and I would think that the primary current is flowing from the 400 volt line, through some of the primary windings but instead of returning via the other 400 volt line with the fuse removed it is flowing to ground via that earth on the secondary windings. This would also explain why that fuse FU 1 is blowing, the impedance from that line to ground is to low and so the fuse blows, looks like a transformer fault. Can you get another transformer or get that one insulation tested ?

 

[Duffman]

I hope Roy and I don't cross paths with suggestions, but after reading the online operator's manual for the FS 30 Elite, I was wrong about the rotary switch and the auxiliary start/stop contacts. The rotary switch is the thermal overload protection, but the controls to turn on and off the machine are on the side panel. If I understand the manual, you turn on the machine by pressing the white button and turn off the machine by engaging the emergency stop button.

There appears to be something wrong with your machine if the start button (Item C in the illustration below) is illuminating as soon as you rotate the switch (Item B in the illustration below). The light in the start button should only illuminate when the button is pushed and the machine is running. The light on the side panel (Item D in the illustration below) should illuminate as soon as you turn the switch.

I've never seen the motor brake release selector (Item E in the illustration below), so this is new territory for me. It is not identified in the electrical schematic. However, it is interesting that the manual states the motor brake releases 20 seconds after activation of the selector switch and you are observing the motor stopping after 20 seconds. Are you sure the brake release switch is in the correct position?

View attachment 153690

Below is an annotated section from the electrical schematic showing the components identified above.

View attachment 153689

Hi Mike, thanks for identifying all the parts on the diagram, it’s great to know what they are. I don’t have the switch marked E on my machine. So we can rule that one out.

 

[Duffman]

Yes that is it's designed output but with a 400 volt input, if you only have one side connected then you will not have 400 volts present so the output would be lower.

This is progress, what this is saying is that there is enough power for the light but not enough to operate the contactor and I would think that the primary current is flowing from the 400 volt line, through some of the primary windings but instead of returning via the other 400 volt line with the fuse removed it is flowing to ground via that earth on the secondary windings. This would also explain why that fuse FU 1 is blowing, the impedance from that line to ground is to low and so the fuse blows, looks like a transformer fault. Can you get another transformer or get that one insulation tested ?

Hi Roy, this is great news that we have identified the problem. What is involved in doing a insulation test on the transformer? Is this something I can do or do I have to bring it to someone.
on a side note would it help or be of any benefit if I connected the red wires on the secondary side of transformer to the output of a yellow box 110v transformer. Would this help to identify any problems?

 

[RichieG]

Where did that wiring diagram come from? Is it definitely the correct one?
What you're finding seems odd doesn't fit the drawing.
Personally I'd do some point to point continuity testing with the machine dead, to establish that the drawing is correct.
This is the safest and least intrusive method.
Take care to eliminate any parallel paths, for example through the transformer.

 

[Spectric]

At this point we know we have a machine that works when the contactor is pulled in so that side is not a problem. We know the control circuit works and the machine operates but the fuse FU 1 blows and yet it still works. We also know that removing the ground wires from the transformer stops the machine working although the light comes on which tells me that there is a current flow through the primary windings to ground. It all points to that transformer being faulty, so bearing in mind that a site transformer is 110 volts centre tapped to earth, ie 55 - 0 - 55 volts it might not be helpful to try and power the control circuit this way. To test that transformer you need an insulation tester, often referred to as a mega which test resistance under an applied voltage to indicate any breakdown in the windings, I would say the best way forward is to just replace that transformer. Can you get one of these easily ?

RS list several but with a 115 volt output.

Farnell list them with 110 output but no stock even with a 230 volt primary https://uk.farnell.com/c/transforme...primary-voltages=400v&secondary-voltages=110v

Looks like the 400 - 24 and 230 - 24 volt are more common and stocked.

 

[MikeJhn]

If this is a TNCS supply and removing the earth stops the machine from working, would this not indicate a neutral supply fault?

 

[Spectric]

would this not indicate a neutral supply fault

This machine only uses two of the phases (400 volts) to supply the control circuit transformer and has no neutral. But earth and neutral are really the same, connected at the supply in a TNCS (PME) system or the starpoints are grounded at the substation.

 

[MikeJhn]

I know they are the same, that's why I suggested it could be a neutral fault with the earth removed and the machine not running, haven't read the whole thread and was just a random thought

 

[Duffman]

At this point we know we have a machine that works when the contactor is pulled in so that side is not a problem. We know the control circuit works and the machine operates but the fuse FU 1 blows and yet it still works. We also know that removing the ground wires from the transformer stops the machine working although the light comes on which tells me that there is a current flow through the primary windings to ground. It all points to that transformer being faulty, so bearing in mind that a site transformer is 110 volts centre tapped to earth, ie 55 - 0 - 55 volts it might not be helpful to try and power the control circuit this way. To test that transformer you need an insulation tester, often referred to as a mega which test resistance under an applied voltage to indicate any breakdown in the windings, I would say the best way forward is to just replace that transformer. Can you get one of these easily ?

RS list several but with a 115 volt output.

Farnell list them with 110 output but no stock even with a 230 volt primary https://uk.farnell.com/c/transforme...primary-voltages=400v&secondary-voltages=110v

Looks like the 400 - 24 and 230 - 24 volt are more common and stocked.

Perfect I’ll look into getting a new transformer. Would this one work ERSCT200 Eris Industrial 200VA Panel Transformer 230/400V Primary - 12/24/48/110/240V Secondary | YESSS Electrical

 

[Spectric]

That looks ok, states a 400 volt primary but gives the option of 230 volts and you get the 110 volt secondary.

 

[Spectric]

Any news on how this is going ?

 

[Duffman]

Any news on how this is going ?

Hi Roy, I ordered the part from a company in England but they don’t deliver to Ireland so I had to get it sent to a friend in Northern Ireland. The part arrived today and I have to get it now and get it installed. I Will give you an update when I get the part and get it installed. Thanks for checking in.

 

[Duffman]

@Spectric @MikeK

Hi Roy and Mike,
I am just following up with my planner electrical issue. As I said earlier I ordered a new transformer from a company in England and had it delivered to a friend in Northern Ireland. I picked up the part this weekend and fitted it today. Images below. I am delighted to say it worked. The machine is back to running perfectly. I ran it for 10 minutes straight with no problems at all. It does not cut out or blow fuses any more.

I just wanted to say a massive thank you to both of you for taking the time and effort to engage with me and providing such detailed answers and support to figure out the problem with the machine. I had 3 different people look at the machine over the last few months and no one could tell me what was wrong. It was great to chat with people who knew what they were talking about inside out and upside down. This really is a great forum.

Now that the machine is back up and running the wife has a coffee table lined up for me to make. Thanks again lads.

 

[Spectric]

Glad to hear your issues are sorted and the machine is now running ok. Yes this forum is like Carling, probably the best around.