Sensitivity to high voltages

[GBDamo]

The electronics within our machines are manufactured to be tolerant of 220V +/-10%. many components have a max 250V allowance.

Now we all know that although our domestic supplies are supposed to be 230V they can vary widely, I personally have measured 257V on one supply.

What in your opinion is the most cost effective way of limiting the supply voltage without causing the to trip due to high voltage conditions.

This is to protect a single device (~3-5 Kw) not the entire installation.

Any useful ideas appreciated.

 

[Darkwood]

You equipment should be tolerable of the voltages of the market it sells into, it is common to see voltages 240v - 250v, also the equipment if it is prone to mains transients it should incorporate it's own protective measures.
Are these machines ones you build yourself or just machinery you have on site?

PS if you have measured 257volts on a meter with true rms then you should report the findings to DNO, this indicates there supply in in breach of their own regulations currently 253volts, if you have a cheap meter then be weary of the reading been accurate.

 

[Pete999]

The electronics within our machines are manufactured to be tolerant of 220V +/-10%. many components have a max 250V allowance.

Now we all know that although our domestic supplies are supposed to be 230V they can vary widely, I personally have measured 257V on one supply.

What in your opinion is the most cost effective way of limiting the supply voltage without causing the to trip due to high voltage conditions.

This is to protect a single device (~3-5 Kw) not the entire installation.

Any useful ideas appreciated.

The electronics within our machines are manufactured to be tolerant of 220V +/-10%. many components have a max 250V allowance.

Now we all know that although our domestic supplies are supposed to be 230V they can vary widely, I personally have measured 257V on one supply.

What in your opinion is the most cost effective way of limiting the supply voltage without causing the to trip due to high voltage conditions.

This is to protect a single device (~3-5 Kw) not the entire installation.

Any useful ideas appreciated.

Voltage stabiliser, UPS

 

[GBDamo]

You equipment should be tolerable of the voltages of the market it sells into, it is common to see voltages 240v - 250v, also the equipment if it is prone to mains transients it should incorporate it's own protective measures.
Are these machines ones you build yourself or just machinery you have on site?

PS if you have measured 257volts on a meter with true rms then you should report the findings to DNO, this indicates there supply in in breach of their own regulations currently 253volts, if you have a cheap meter then be weary of the reading been accurate.

Thanks for the swift response, the equipment is "supposed" to be fit for purpose but we have one machine that is throwing up a protection fault code that indicates it has seen an overvoltage occurrence. This shuts the machine down and requires a manual reset. After multiple resets the fault becomes permanent and requires a replacement pcb.

We have two options in my mind, re-engineer to be more tolerant to overvoltage or install an up front voltage regulator but which product is best???

the Voltage was measured by a true RMS meter but not an expensive one.

 

[GBDamo]

Voltage stabiliser, UPS

Do you recommend any particular products??

 

[Darkwood]

With voltages measured that high I would first double check and get onto the DNO, last time I had 255v they were out within 2 hrs and came back next day to alter TX tapping, there is also the issue that this problem may not be a supply problem to your machine, there could be problems within your machinery that are spiking and blowing the PCB - if this is the case replacing the PCB will only possibly subject the new one to the same problems...
Without knowing what the machine is, its rating, how the PCB interacts with the rest of the machine etc it is impossible to advise on a solution as each scenario requires its own solution to suit. I take it your works in in close proximity to the sub station?

 

[GBDamo]

With voltages measured that high I would first double check and get onto the DNO, last time I had 255v they were out within 2 hrs and came back next day to alter TX tapping,

Like I said, it was an inexpensive meter..

....there is also the issue that this problem may not be a supply problem to your machine, there could be problems within your machinery that are spiking and blowing the PCB - if this is the case replacing the PCB will only possibly subject the new one to the same problems...

This is not only possible but quite likely, my request here is an attempt at grabbing a "low hanging fruit" solution. It may not be the most likely candidate but it is relatively cheap and easy to test hypothesis. Ruling out supply overvoltage gives a little more weight to to any push back we have with our supplier.

Without knowing what the machine is, its rating, how the PCB interacts with the rest of the machine etc it is impossible to advise on a solution as each scenario requires its own solution to suit. I take it your works in in close proximity to the sub station?

I can't go into too much detail but essentially the PCB manages/inverts the power to a compressor using a TRIAC array. The manufacturer is adamant that it is only a problem in the UK hence why i'd like to rule out supply voltage.

As for the sub station, of those that have shown this fault many have been very close to pole mounted transformers but not sub stations.

Thanks for your thoughs.

 

[Darkwood]

If it is indeed close to a Pole Tx then it is a likely suspect, l have known close proximity be an issue especially nuisance tripping of earth leakage devices, when you say close proximity are we talking meter or a few hundred. You may be getting unwanted transients so the first thing would be fitting an anti surge unit and also ensuring the voltage is within limits, if your meter is True RMS then it should be fine to rely on assuming you get it calibrated regularly, if unsure use 2 meters and if they agree it tends to mean they are correct.
As you cannot provide info on the machine I cannot offer other solutions but would a small VSD not be an option, these will usually have integral filters, Triac Arrays are fine and a cheap solution but they have their disadvantages but lack info to comment further and appreciate if you cannot disclose.

 

[GBDamo]

If it is indeed close to a Pole Tx then it is a likely suspect, l have known close proximity be an issue especially nuisance tripping of earth leakage devices, when you say close proximity are we talking meter or a few hundred. You may be getting unwanted transients so the first thing would be fitting an anti surge unit and also ensuring the voltage is within limits, if your meter is True RMS then it should be fine to rely on assuming you get it calibrated regularly, if unsure use 2 meters and if they agree it tends to mean they are correct.
As you cannot provide info on the machine I cannot offer other solutions but would a small VSD not be an option, these will usually have integral filters, Triac Arrays are fine and a cheap solution but they have their disadvantages but lack info to comment further and appreciate if you cannot disclose.

I know more info would make things easier so thanks for persevering.

By VSD do you mean voltage suppression device? and if so can you point me to a product that can handle 32Amp whilst clamping the output to 230/240V without tripping on overvoltage?
My googling has led me to £600-£1000 power conditioners but this seems like a massive sledgehammer for a tiny nut.

 

[Darkwood]

No, you express it runs a compressor so I make the assumption we are talking a motor, a VSD is a variable speed drive but i may be barking up the wrong tree here with the limited info', a drive would have built in filters usually and are more tolerant to input voltage ranges, it of course would mean altering the control of the machine and it would void any warranties and would have to meet machinery code standards.

 

[static zap]

..... The manufacturer is adamant that it is only a problem in the UK hence why i'd like to rule out supply voltage.
....
.

Are they comparing us to European 230 ... or usa 120 ?
Better dv/dt specced triacs are more expensive ...
So may be a price point thing ..while watching the pennies !

 

[GBDamo]

No, you express it runs a compressor so I make the assumption we are talking a motor, a VSD is a variable speed drive but i may be barking up the wrong tree here with the limited info', a drive would have built in filters usually and are more tolerant to input voltage ranges, it of course would mean altering the control of the machine and it would void any warranties and would have to meet machinery code standards.

Yes, replacing integral components is a no go for the reasons you state hence me looking for an upfront device.

 

[GBDamo]

Are they comparing us to European 230 ... or usa 120 ?
Better dv/dt specced triacs are more expensive ...
So may be a price point thing ..while watching the pennies !

EU 230V, as for the components we can only assume you're correct but to be honest we don't even know which exact component on the PCB is failing.
If I can guarantee the incoming voltage is 230+/-10% I can kick the fault back to the manufacturer. If clamping the voltage cures the fault then it's just a matter of retro-fitting a suitable device.

 

[Darkwood]

It depends on the power demands of the machine but I would be looking to getting surge protection either a cheaper option at the machine or more costly one at the origin of your incoming supply. These will not limit voltage level as such but will absorb any spikes coming down the supply.

http://www.hager.co.uk/files/download/0/4540_1/0/Hager Guide to Surge Protection.pdf

 

[dmxtothemax]

Your voltage is supposed to be 230v ?
But is it in reality ? Ours is officially 230v but in reality it is 240v.
But that is still within the official margin of +10%.
most electrical appliances will handle even 257v.
But some sensitive electronics may not.
So if your mains varies that much then don't use sensitive
electronics that cannot handle it.
Apart from using a UPS there is no easy way out !
What are you having a problem with ?