control power transformer
- Thread starter Elekk
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Depends what you are building.
It's normal practice on industrial machinery to use 24V ac for control circuits. 110V centre tapped earth (i.e 55, 0 , 55) is also common.
Tell us more about what you are doing.
It's normal practice on industrial machinery to use 24V ac for control circuits. 110V centre tapped earth (i.e 55, 0 , 55) is also common.
Tell us more about what you are doing.
If you are going to comply with 60204-1 then you must have a transformer with primary & secondary overcurrent protection.
If you don't comply with 60201-1 then it is doubtful you will comply with PUWER98 which is statutory, thus you are open to prosecution.
As Dave says, please give us some more info.
If you don't comply with 60201-1 then it is doubtful you will comply with PUWER98 which is statutory, thus you are open to prosecution.
As Dave says, please give us some more info.
What is the motor fitted to, how many control devices?
There is more to this than it may first appear.
Do you have a neutral at the supply point?
if not you may need a 400V 2 or 3ph to 230V.
It would be better if the transformer were an isolating transformer also.
As this is verging on statute law then it is a bit more controlled than 7671 stuff.
Is this for a new machine, an existing machine if an existing machine is it CE marked?
There is more to this than it may first appear.
Do you have a neutral at the supply point?
if not you may need a 400V 2 or 3ph to 230V.
It would be better if the transformer were an isolating transformer also.
As this is verging on statute law then it is a bit more controlled than 7671 stuff.
Is this for a new machine, an existing machine if an existing machine is it CE marked?
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And shall we start discussing the interlocking, guarding and emergency stop arrangements?
What category of stop system does your risk assessment say it needs?
What category of stop system does your risk assessment say it needs?
Dave,
This is the point though, it is statute law mate you can't avoid these things they have to be done, employers have a statute law duty to comply and thus you must comply also so yes they must be considered, end of story.
A PUWER assessment must show up any inadeqacies and this is required under the PUWER regs mate take the mick as much as you want.
If you come up against an expert witness then you would get into big trouble if you have not complied even as the "contractor".
Further more neither the employer of you as the contractor can shirk the responsibility.
This is the point though, it is statute law mate you can't avoid these things they have to be done, employers have a statute law duty to comply and thus you must comply also so yes they must be considered, end of story.
A PUWER assessment must show up any inadeqacies and this is required under the PUWER regs mate take the mick as much as you want.
If you come up against an expert witness then you would get into big trouble if you have not complied even as the "contractor".
Further more neither the employer of you as the contractor can shirk the responsibility.
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Is that addressed at me?
I was not taking the mick.
As someone who used to design, build and commission control systems for industrial machinery I know it all well, or at least I did, but it's 8 years since I have referred to a copy of 60204 and I don't have one of my own so I am a bit rusty.
So I was perfectly serious addressing the comment to the OP that he needs to be considering ALL aspects of this machine, not just whether he needs a transformer to operate a control relay.
Sorry Dave,
I thought you were having a go at my post a 1000 appologies, so yes you are correct there is more to this than just a control transformer!
Sorry again for getting the wrong end of the stick, it's late, I have had a bad computer day and have raided the fridge, well that's my excuse.
Sorry again.
I thought you were having a go at my post a 1000 appologies, so yes you are correct there is more to this than just a control transformer!
Sorry again for getting the wrong end of the stick, it's late, I have had a bad computer day and have raided the fridge, well that's my excuse.
Sorry again.
The motor is for an industrial pump, and yes IEC 60204 applies in this case. The last paragraph of IEC 60204 section 9.1.1 says that control transformers are not required for machines with a single motor starter and/or a maximum of two control devices. I just need an explanation of this last paragraph of section 9.1.1 of IEC 60204.
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Yes is sounds like we (me?) jumped to conclusions thinking you might have some large dangerous machine there.
A simple pump with what effectively is a direct on line starter should be okay as you describe.
You still need to do a risk assessment, but in the case of an enclosed pump with no external moving parts, the risk of injury is exceedingly low, so no need for guards, interlocks etc.
Perhaps to cover your nether regions, you might want to write down something to that effect?
P.S you should see what some domestic appliance makers do: When my washing machine broke down and I had to fault find it, I found the on / off switch broke the NEUTRAL feed to the control board. Very bad, but they seem to get away with it.
A simple pump with what effectively is a direct on line starter should be okay as you describe.
You still need to do a risk assessment, but in the case of an enclosed pump with no external moving parts, the risk of injury is exceedingly low, so no need for guards, interlocks etc.
Perhaps to cover your nether regions, you might want to write down something to that effect?
P.S you should see what some domestic appliance makers do: When my washing machine broke down and I had to fault find it, I found the on / off switch broke the NEUTRAL feed to the control board. Very bad, but they seem to get away with it.
The motor is controlled by variable-speed-drive. There is no starter. I am assuming that because it is a single motor, so control transformer is not required for the control circuit of variable-speed-drive. Please let me know comments.
You will need a control transformer with the VSD, does the VSD not require "other" control voltages?
You will have a remote start/stop buttons and a speed control device?
You will have a remote start/stop buttons and a speed control device?
and then there are the boilers with a fused neutral
The control voltage of VSD is 230V AC. There is no 24V DC.
There are two control circuits. The first circuit is from VSD to PLC and tells the PLC that at what speed the motor is running at this time. The second circuit is from PLC to VSD and tells the VSD at what speed motor should run. The VSD also has a Hand-Off-Auto switch.
As per 60204 9.1.1, if there are a maximum of two interlock-devices, then control-transformer is not required.
I want to know what does
There are two control circuits. The first circuit is from VSD to PLC and tells the PLC that at what speed the motor is running at this time. The second circuit is from PLC to VSD and tells the VSD at what speed motor should run. The VSD also has a Hand-Off-Auto switch.
As per 60204 9.1.1, if there are a maximum of two interlock-devices, then control-transformer is not required.
I want to know what does
You need a transformer with the system you describe in your last post as you will have remote cabling and remote devices.
Actually I know what I am doing. On the wiring diagram at page H.23 at the link below, on bottom right side it says that the control voltage between points RA & RC can either be 250VAC or 24VDC. In our case it is 250VAC.
http://www.gepowercontrols.com/ex/resources/literature_library/catalogs/control_automation/downloads/45289_GPC_ed3_EN_Speed_drive_units.pdf
http://www.gepowercontrols.com/ex/resources/literature_library/catalogs/control_automation/downloads/45289_GPC_ed3_EN_Speed_drive_units.pdf
Elekk,
Please remember all I know of this job & you really is what I have read in this thread, I have seen your posts before, but can't recall any good or bad, so I am forgetting anything that has gone before, so I don't know your background.
Now if I have the wrong end of the stick then please accept my apologies.
As I don't know your background or your status, please take these comments in the good faith that they are intended.
You need a transformer.
What are you programming the RA/RC NO pair to be?
Are they to be the drive running signal, if so to where?
What else is being put into this chain?
The drive does not seem to have any safety functionality built in?
What PLC are you using?
Who is doing the design work and signing it off?
IF 60204-1 applies then it is likely that the LVD, the EMCD & possibly the MD also apply.
This will mean a full FMEA and consideration of the SRPCS.
Have you done this sort of thing before?
Is this an in house project for your employer, or are you a self employed contractor doing this as a service for a client?
HTH
Please remember all I know of this job & you really is what I have read in this thread, I have seen your posts before, but can't recall any good or bad, so I am forgetting anything that has gone before, so I don't know your background.
Now if I have the wrong end of the stick then please accept my apologies.
As I don't know your background or your status, please take these comments in the good faith that they are intended.
You need a transformer.
What are you programming the RA/RC NO pair to be?
Are they to be the drive running signal, if so to where?
What else is being put into this chain?
The drive does not seem to have any safety functionality built in?
What PLC are you using?
Who is doing the design work and signing it off?
IF 60204-1 applies then it is likely that the LVD, the EMCD & possibly the MD also apply.
This will mean a full FMEA and consideration of the SRPCS.
Have you done this sort of thing before?
Is this an in house project for your employer, or are you a self employed contractor doing this as a service for a client?
HTH
Whatever he said above, is what I`d have said, if I know what the flip he was talking about.............
What I DO know, Elekk, is this:
If either of Canoeboy or Sidewinder tell me they think something - I`m going to believe them. Especially in a scenario such as this, they are two of the most clued-up guys I`ve known.......I wouldn`t be arguing.
But....IF you "know what you are doing", then go ram 250VAC up its bum, and see what happens. I believe I know............... bad day explode
What I DO know, Elekk, is this:
If either of Canoeboy or Sidewinder tell me they think something - I`m going to believe them. Especially in a scenario such as this, they are two of the most clued-up guys I`ve known.......I wouldn`t be arguing.
But....IF you "know what you are doing", then go ram 250VAC up its bum, and see what happens. I believe I know............... bad day explode
