OP
inie meanie
Yes you should rate your coils for your own current range.20 amps is more than enough for me.
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I
Yes you should rate your coils for your own current range.20 amps is more than enough for me.
B
Otherwise the circuits I have seen have inputs protected with clamps, use opto isolators etc. I see no reasons why they could not meet CE so long as the build design is sensible.
I would try and tempt you from the off the shelf PID controller though. There are plenty of ready made microcontroller solutions you can buy for £20 or so. Most have worked examples showing you how to make an ADC readings and drive a DAC outputs (or analogue out using driving resistors from your output ports).
If your PID controller has built in analogue and digital buffers then I guess its the best thing to use. Your system is then pretty much COTS and you have a £200 EMMA! Which PID controller are you looking at BTW?
P
To meet CE radiated and conducted emissions you need a filter designed for dirty circuits like thyristors. An off the shelf one is about £50. You also need to protect for failure mechanisms which could cause a fire so fuse is required for the thyristor or crydom unit. An MCB is required because the crydom unit and thyristors have a significant leakage current when off so regs demand a switch as its above 25VA
I have just been costing it up and it comes to more like £500. I am also having problems sourcing the PID controller to match the 10 V o/p cts that EMMA uses. they need a load > 2Mohms and the controller needs an external analogue set point. so I have been tempted to the dark side by my son and a colleague who have offered to lay out a pcb and do the micro controller programming . This should bring the cost to under £250
B
I think that you are best going with a microcontroller. As pointed out the Arduino projects at openenergy monitor forums are well worth looking at.
There are examples showing how to log your systems performance to the cloud and then you can monitor your system from your smart phone or web browser. You would struggle to do that with a PID controller + the extra cost of the PID controller.
P
B
S
S
B
Yes, I would go all the way on the TRIAC.
Generating the pulse yourself would be easier than interfacing to the Crydom.
To generate the pulse you just need to detect zero cross - a diode on a digital input would do (some braver sole may forget the diode and just use the digital input's ESD protection). Arm a counter counting down from the DIO trigger and you're done. OK some calibration needed. All microcontrollers will have a counter and/or PWM on board.
With the Crydom you have to generate and buffer an analogue signal using a DAC or resistor chain. Needing an onboard DAC is going to heavily cut down on your microcontroller choice. There are plenty available but perhaps not on a ready built evaluation boards.
I am digital & find analogue tricky, perhaps you're the other way. The timer / PWM arm software is just a few lines and there will be plenty of examples available.
If you use DIO then you just need an analogue circuit to protect the CT inputs. If you buy an microcontroller evaluation board then there should be space enough in the prototyping area to fit that circuit.
Without knowing your CTs cost I would say that your down to £100 or so with your line filter.
Evaluation controller £30 + £5 TRIAC + Case&Heatsink + £5 CT clipper + CTs + On/Off switch & fuse + £30 line filter.
P
Yes I find the analogue easy as I have experience in phase lock loops and analogue control loops. The crydom is attractive only as no interfacing at mains voltage is required and I don't have to design a snubber which is notoriously difficult to test without creating a bucket full of dead bits. I may also consider the option of an entirely analogue loop with a micro-controller to supervise,feed a display of power, logging and some load switching. I need to get on and build a prototype ( pressure from a queue of friends who followed my advice with the PV system and want the immersion controller ) and so will probably postpone the triac for a phase 2 cost reduction. Many thanks for the inputs very useful
Sacreblue! I can sell you one for under half that or as a kit for even less, but fine if you prefer the challenge of designing your own. Mine do work, as stated by early adopters such as:-
From a retired CEO of a housing authority:-
After some fine tuning the I2 worked well. I can tell from my web based power monitoring system that the unit cuts in and out at the right times. On a sunny day it provides all the hot water we need.
From a qualified electrician:-
The unit is working really well and keeping the thermal store topped up with heat on the days where I might not have usually produced quite enough from the solar thermal system.
I was monitoring the system the other afternoon and taking measurements with my clamp on wattmeter. This can differentiate between import and export power and shows a negative reading on export. Watching the meter keeping the power exported to around the 50-100W mark while the PV system was generating 1-1.2 kW, I observed the current to the immersion was gradually reduced down to 0.3 amps and then go off as the sun dropped in the sky.
I will probably be looking to buy another unit from you to install in my Mother's house as she has just had a PV system installed.
(To be fair not everyone is yet getting that low an export but it's an adjustment issue I think).
From an airline pilot:-
I have now the means to measure import/export accurately! Your device works perfectly and does exactly what you say! Very happy.
T
B
Please share for others to build with/on. How did you go about it, which design did you use?
P
What is your professional status, are you a registered company?
P
hmm.... is it me and my mate Fred who knows a lot about lectric stuff?
T
I'm sorry to have kept you waiting; I don't visit the forum every day.
The device I mentioned is a being tested at an installation in Southampton. When we're completely satisfied with it's performance I'll post a thread giving more details.
S
P
I suspect that they do not believe that their designs would survive scrutiny, and hide behind this 'patent' rubbish. If I am wrong - please post your patent registration details here and surprise me!
I have no commercial interest, but if you want to see how my system performs click here to see real live stats.
...and to see how I got there, see my blog powerhub.info
It would be good for the commercial developers to do similar...
I
As a follow up to the filters quote. I have purchased a Schaffner 2060-16/06 for £2.88 off ebay. All fited within half an hour, just at the output of the Triac. I have since found out that that all electronic apparatus sold or taken into service within the EU must comply with the essential requirements of the EMC directive 2004/108/EC. Failure to do so is a criminal offence in the uk.
Sounds a bit heavy handed but you can buy these very effective two stage filters on ebay very cheaply in an auction or as a buy it now , see links
eBay - The UK's Online Marketplace
eBay - The UK's Online Marketplace
http://www.ebay.co.uk/itm/250892028047?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648 other auction sites are available :- )
or just search for 'Schaffner FN2020A-20-06 ' these are for £12 inc delivery so too cheep not too!
Thanks to the members for bringing this to my attention.
S
Discuss Immersion Heater - PV electricity in the Central Heating Systems area at ElectriciansForums.net
Yes you should rate your coils for your own current range.20 amps is more than enough for me.
OP
bradburts
Please elaborate. Are you talking about the PFC chopping the AC? The EMMA seems to get by with a PFC and off the shelf filter. What filter would you use?very little protection and no filtering none of them would pass CE.
Otherwise the circuits I have seen have inputs protected with clamps, use opto isolators etc. I see no reasons why they could not meet CE so long as the build design is sensible.
Agree, being a lazy engineer is usually best.My conclusion based on the prototypes and entry's on this forum is to be lazy and go for the AT20B10/ AT50B10 sensors, crydom phase controller, i/p filter, packaged power supply and an off the shelf PID controller ( not yet selected any suggestions welcome ). This is very expensive but I don't have the hassle of designing and building a pcb. The analogue cts were std stuff. I used precision rectifiers for the ct interface and then a simple type 2 op amp integrator
I would try and tempt you from the off the shelf PID controller though. There are plenty of ready made microcontroller solutions you can buy for £20 or so. Most have worked examples showing you how to make an ADC readings and drive a DAC outputs (or analogue out using driving resistors from your output ports).
If your PID controller has built in analogue and digital buffers then I guess its the best thing to use. Your system is then pretty much COTS and you have a £200 EMMA! Which PID controller are you looking at BTW?
OP
pmcalli
Please elaborate. Are you talking about the PFC chopping the AC? The EMMA seems to get by with a PFC and off the shelf filter. What filter would you use?
Otherwise the circuits I have seen have inputs protected with clamps, use opto isolators etc. I see no reasons why they could not meet CE so long as the build design is sensible.
Agree, being a lazy engineer is usually best.
I would try and tempt you from the off the shelf PID controller though. There are plenty of ready made microcontroller solutions you can buy for £20 or so. Most have worked examples showing you how to make an ADC readings and drive a DAC outputs (or analogue out using driving resistors from your output ports).
If your PID controller has built in analogue and digital buffers then I guess its the best thing to use. Your system is then pretty much COTS and you have a £200 EMMA! Which PID controller are you looking at BTW?
To meet CE radiated and conducted emissions you need a filter designed for dirty circuits like thyristors. An off the shelf one is about £50. You also need to protect for failure mechanisms which could cause a fire so fuse is required for the thyristor or crydom unit. An MCB is required because the crydom unit and thyristors have a significant leakage current when off so regs demand a switch as its above 25VA
I have just been costing it up and it comes to more like £500. I am also having problems sourcing the PID controller to match the 10 V o/p cts that EMMA uses. they need a load > 2Mohms and the controller needs an external analogue set point. so I have been tempted to the dark side by my son and a colleague who have offered to lay out a pcb and do the micro controller programming . This should bring the cost to under £250
Last edited by a moderator:
OP
bradburts
Would you mind posting a link to a suitable unit?To meet CE radiated and conducted emissions you need a filter designed for dirty circuits like thyristors. An off the shelf one is about £50.
Thats a lot! I was expecting a lot less but I have not looked at the cost of the CTs.I have just been costing it up and it comes to more like £500.
I think that you are best going with a microcontroller. As pointed out the Arduino projects at openenergy monitor forums are well worth looking at.
There are examples showing how to log your systems performance to the cloud and then you can monitor your system from your smart phone or web browser. You would struggle to do that with a PID controller + the extra cost of the PID controller.
OP
pmcalli
Would recommend a two stage filter Buy Power Line Filter 2 stage chassis mount filter,16A Schaffner FN 2060-16/06 online from RS for next day delivery. this one is under £30 you can get a single stage for half that but not sure it would pass CE. DIN rail mounted ones are available as well but horribly expensive £100 touch
OP
bradburts
Thanks.
OP
suntrap
In that case, how about going all the way and using a triac (opto-isolated ones available for about £5) rather than the Crydom controller? Get a sniff of AC voltage and generate the trigger pulses yourself.I have been tempted to the dark side by my son and a colleague who have offered to lay out a pcb and do the micro controller programming . This should bring the cost to under £250
OP
suntrap
Or if you really wanted to economise you could buy a couple of washing machine filters (they seem to be single-stage) and put them in series. They can handle the current. I did wonder if the suppression would be less effective due to the size of a washing machine motor, but the component values seem to be comparable.Would recommend a two stage filter Buy Power Line Filter 2 stage chassis mount filter,16A Schaffner FN 2060-16/06 online from RS for next day delivery. this one is under £30 you can get a single stage for half that but not sure it would pass CE. DIN rail mounted ones are available as well but horribly expensive £100 touch
OP
bradburts
In that case, how about going all the way and using a triac (opto-isolated ones available for about £5) rather than the Crydom controller? Get a sniff of AC voltage and generate the trigger pulses yourself.
Yes, I would go all the way on the TRIAC.
Generating the pulse yourself would be easier than interfacing to the Crydom.
To generate the pulse you just need to detect zero cross - a diode on a digital input would do (some braver sole may forget the diode and just use the digital input's ESD protection). Arm a counter counting down from the DIO trigger and you're done. OK some calibration needed. All microcontrollers will have a counter and/or PWM on board.
With the Crydom you have to generate and buffer an analogue signal using a DAC or resistor chain. Needing an onboard DAC is going to heavily cut down on your microcontroller choice. There are plenty available but perhaps not on a ready built evaluation boards.
I am digital & find analogue tricky, perhaps you're the other way. The timer / PWM arm software is just a few lines and there will be plenty of examples available.
If you use DIO then you just need an analogue circuit to protect the CT inputs. If you buy an microcontroller evaluation board then there should be space enough in the prototyping area to fit that circuit.
Without knowing your CTs cost I would say that your down to £100 or so with your line filter.
Evaluation controller £30 + £5 TRIAC + Case&Heatsink + £5 CT clipper + CTs + On/Off switch & fuse + £30 line filter.
OP
pmcalli
Yes, I would go all the way on the TRIAC.
Generating the pulse yourself would be easier than interfacing to the Crydom.
To generate the pulse you just need to detect zero cross - a diode on a digital input would do (some braver sole may forget the diode and just use the digital input's ESD protection). Arm a counter counting down from the DIO trigger and you're done. OK some calibration needed. All microcontrollers will have a counter and/or PWM on board.
With the Crydom you have to generate and buffer an analogue signal using a DAC or resistor chain. Needing an onboard DAC is going to heavily cut down on your microcontroller choice. There are plenty available but perhaps not on a ready built evaluation boards.
I am digital & find analogue tricky, perhaps you're the other way. The timer / PWM arm software is just a few lines and there will be plenty of examples available.
If you use DIO then you just need an analogue circuit to protect the CT inputs. If you buy an microcontroller evaluation board then there should be space enough in the prototyping area to fit that circuit.
Without knowing your CTs cost I would say that your down to £100 or so with your line filter.
Evaluation controller £30 + £5 TRIAC + Case&Heatsink + £5 CT clipper + CTs + On/Off switch & fuse + £30 line filter.
Yes I find the analogue easy as I have experience in phase lock loops and analogue control loops. The crydom is attractive only as no interfacing at mains voltage is required and I don't have to design a snubber which is notoriously difficult to test without creating a bucket full of dead bits. I may also consider the option of an entirely analogue loop with a micro-controller to supervise,feed a display of power, logging and some load switching. I need to get on and build a prototype ( pressure from a queue of friends who followed my advice with the PV system and want the immersion controller ) and so will probably postpone the triac for a phase 2 cost reduction. Many thanks for the inputs very useful
I have just been costing it up and it comes to more like £500.
Sacreblue! I can sell you one for under half that or as a kit for even less, but fine if you prefer the challenge of designing your own. Mine do work, as stated by early adopters such as:-
From a retired CEO of a housing authority:-
After some fine tuning the I2 worked well. I can tell from my web based power monitoring system that the unit cuts in and out at the right times. On a sunny day it provides all the hot water we need.
From a qualified electrician:-
The unit is working really well and keeping the thermal store topped up with heat on the days where I might not have usually produced quite enough from the solar thermal system.
I was monitoring the system the other afternoon and taking measurements with my clamp on wattmeter. This can differentiate between import and export power and shows a negative reading on export. Watching the meter keeping the power exported to around the 50-100W mark while the PV system was generating 1-1.2 kW, I observed the current to the immersion was gradually reduced down to 0.3 amps and then go off as the sun dropped in the sky.
I will probably be looking to buy another unit from you to install in my Mother's house as she has just had a PV system installed.
(To be fair not everyone is yet getting that low an export but it's an adjustment issue I think).
From an airline pilot:-
I have now the means to measure import/export accurately! Your device works perfectly and does exactly what you say! Very happy.
OP
trebormint
we have developed a system which connects to a standard 3KW immersion heater which will reduce the power consumption to a more acceptable 1.2KW. It monitors the array output & household consumption & will switch the heater on when the PV is generating enough & switch the heater off when either the PV isn't producing enough or if the household consumption increases above the demand for the PV.
OP
bradburts
Sounds interesting.we have developed a system which connects to a standard 3KW immersion heater which will reduce the power consumption to a more acceptable 1.2KW.
Please share for others to build with/on. How did you go about it, which design did you use?
OP
pauldreed
Who is we?we have developed a system which connects to a standard 3KW immersion heater which will reduce the power consumption to a more acceptable 1.2KW. It monitors the array output & household consumption & will switch the heater on when the PV is generating enough & switch the heater off when either the PV isn't producing enough or if the household consumption increases above the demand for the PV.
What is your professional status, are you a registered company?
Last edited by a moderator:
OP
pauldreed
Wot, 5 day's later and no response??we have developed a system which connects to a standard 3KW immersion heater which will reduce the power consumption to a more acceptable 1.2KW. It monitors the array output & household consumption & will switch the heater on when the PV is generating enough & switch the heater off when either the PV isn't producing enough or if the household consumption increases above the demand for the PV.
hmm.... is it me and my mate Fred who knows a lot about lectric stuff?
Last edited by a moderator:
OP
trebormint
Wot, 5 day's later and no response??
hmm.... is it me and my mate Fred who knows a lot about lectric stuff?
I'm sorry to have kept you waiting; I don't visit the forum every day.
The device I mentioned is a being tested at an installation in Southampton. When we're completely satisfied with it's performance I'll post a thread giving more details.
OP
suntrap
Another commercial product then? Why are people being so clandestine about them? Are they worried that they are infringing patents so are only giving details to people who approach them privately? Doesn't cost anything to make a website giving full details of what you are trying to flog.
OP
pauldreed
I agree Suntrap!Another commercial product then? Why are people being so clandestine about them? Are they worried that they are infringing patents so are only giving details to people who approach them privately? Doesn't cost anything to make a website giving full details of what you are trying to flog.
I suspect that they do not believe that their designs would survive scrutiny, and hide behind this 'patent' rubbish. If I am wrong - please post your patent registration details here and surprise me!
I have no commercial interest, but if you want to see how my system performs click here to see real live stats.
...and to see how I got there, see my blog powerhub.info
It would be good for the commercial developers to do similar...
Last edited by a moderator:
OP
inie meanie
Would recommend a two stage filter Buy Power Line Filter 2 stage chassis mount filter,16A Schaffner FN 2060-16/06 online from RS for next day delivery. this one is under £30 you can get a single stage for half that but not sure it would pass CE. DIN rail mounted ones are available as well but horribly expensive £100 touch
As a follow up to the filters quote. I have purchased a Schaffner 2060-16/06 for £2.88 off ebay. All fited within half an hour, just at the output of the Triac. I have since found out that that all electronic apparatus sold or taken into service within the EU must comply with the essential requirements of the EMC directive 2004/108/EC. Failure to do so is a criminal offence in the uk.
Sounds a bit heavy handed but you can buy these very effective two stage filters on ebay very cheaply in an auction or as a buy it now , see links
eBay - The UK's Online Marketplace
eBay - The UK's Online Marketplace
http://www.ebay.co.uk/itm/250892028047?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2648 other auction sites are available :- )
or just search for 'Schaffner FN2020A-20-06 ' these are for £12 inc delivery so too cheep not too!
Thanks to the members for bringing this to my attention.
Last edited by a moderator:
OP
suntrap
Haha - those cheap power supplies, battery chargers etc you get from the likes of DealExtreme don't have any filter components in them.
Reply to Immersion Heater - PV electricity in the Central Heating Systems area at ElectriciansForums.net
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