Calling All Sparky's (electrics) Need Help With Simple Schematics

[Filby]

Thermostat unit all wired up and completed, ready for heating & cooling devices to be assembled (waiting on peltiers lol). Here are some pics Just a quick question though - I'm using a 150w ceramic lamp that fits in a socket (like a normal light bulb socket) and it has two contacts for wiring which are not labelled. How do I wire this up to the 240? Just two live wires in a circuit to and from the outlet? Or do I need a neutral and live wire.. thanks

Funky, where did you get the panel mount sockets? Ive had a look in a few electrical stores without any luck.

Cheers

Fil

 

[gap]

Jaycar.

Regards

Graeme

 

[funkyyyy]

if average temperature is 25 celcuis and humidity is 75% (not uncommon in summer) then you will see a dew point around 20 degrees celcius. You may want to look at some weather observations for your region and compare average humidity and temperature. If however you have an airtight case for the housing, you will be introducing no extra water vapour into the air under which you sealed the case. To further reduce the amount of water vapour, you could add a bag of silica gel.

I should mention, there will be another "shelf" of wood surrounding the large heatsink so the fans sit flush with the base of the cabinet. I will extend the tubing for the heating, or raise the bulb / fan to compensate for the higher floor in the cabinet. I was thinking of insulating the void in between the two shelves with some polystyrine, or as you said, silica gel bags found in those small dehumidifiers. Thanks

If your controller has a timeout delay or two set points you can use the Peltier to do both the heating and cooling thereby eliminating the need for the ceramic heater (All you need is 2 x 240V relays, which you use to switch the polarity of the voltage to the peltier). Do you have a specification sheet for your controller?

If it doesn't you are going to be rapidly switching between heating and cooling constantly, and you will more than likely sit on the higher side of you temperature set point given that it is far more efficient to heat than cool and your cooling capacity is quite limited.

I know what you mean, I was taking that into consideration however as far as I know my temp controller does not have the ability to do this, I'd rather keep the setup with the ceramic bulb, as in efficient as it may be switching between power constantly, I just need something that works. The whole thing is due in 5-6 weeks, I am going to perfect it for home use after that Here is the data sheet for the controller, just scroll down the page and all the info is there:

http://www.ebay.com.au/itm/All-purpose-Tem...=item2312886353

Cheers guys

 

[mgill]

I should mention, there will be another "shelf" of wood surrounding the large heatsink so the fans sit flush with the base of the cabinet. I will extend the tubing for the heating, or raise the bulb / fan to compensate for the higher floor in the cabinet. I was thinking of insulating the void in between the two shelves with some polystyrine, or as you said, silica gel bags found in those small dehumidifiers. Thanks



I know what you mean, I was taking that into consideration however as far as I know my temp controller does not have the ability to do this, I'd rather keep the setup with the ceramic bulb, as in efficient as it may be switching between power constantly, I just need something that works. The whole thing is due in 5-6 weeks, I am going to perfect it for home use after that Here is the data sheet for the controller, just scroll down the page and all the info is there:

http://www.ebay.com.au/itm/All-purpose-Tem...=item2312886353

Cheers guys

It has two functions, one to set the temperature difference (i.e if you set it to 0.5 degrees and you had a set point of 16 it would cool at 15.5 and cool at 16.5) the other one is called condensor setting, which will delay the time before it starts an action again, i.e. it heats to the set point, turns off for say 5mins before it looks at the temperature again and either heats or cools.

So if you desired you could remove the ceramic heater, and use two relays to swap the polarity of the Peltier to force it to either heat or cool, due to the lack of heating/cooling capacity of the peltier, it will allow for a much smoother temperature control.

If you want to go down this path, I would look at 2x240VAC relays which are DPDT http://www.jaycar.com.au/productView.asp?I...;SUBCATID=979#1, If you want to go down this path I will do a quick picture on how to wire them up.

 

[Deebo]

Anyone know if it is neccesary to drill cooling holes into the stc-1000 enclosure? (I just wired mine up and remembering hearing people say they got pretty warm?)

 

[RdeVjun]

:icon_offtopic:
Pardon the gratuitous poor taste and apologies in advance if it causes offence- pretty sure that's not an accurate diagram of the 'final solution', although, feck it up and you might come close.

 

[mgill]

Anyone know if it is neccesary to drill cooling holes into the stc-1000 enclosure? (I just wired mine up and remembering hearing people say they got pretty warm?)

Looking at the specification sheet supplied by the ebay store power dissipation is pretty low (3W) and its operating temperature is 0-60c. You should be able to get away with it, but if you feel that it is running hot, there is no harm in drilling a couple of holes... if possible always try and aim for cross ventilation.

 

[funkyyyy]

It has two functions, one to set the temperature difference (i.e if you set it to 0.5 degrees and you had a set point of 16 it would cool at 15.5 and cool at 16.5) the other one is called condensor setting, which will delay the time before it starts an action again, i.e. it heats to the set point, turns off for say 5mins before it looks at the temperature again and either heats or cools.

So if you desired you could remove the ceramic heater, and use two relays to swap the polarity of the Peltier to force it to either heat or cool, due to the lack of heating/cooling capacity of the peltier, it will allow for a much smoother temperature control.

If you want to go down this path, I would look at 2x240VAC relays which are DPDT http://www.jaycar.com.au/productView.asp?I...;SUBCATID=979#1, If you want to go down this path I will do a quick picture on how to wire them up.

If I take this route will the cooling / heating effect work? I know it won't be as fast as using a ceramic heater but that is not a problem, just as long as it can reach the desired temperature. The temperature range I'm aiming for won't exceed 13-15C and 30-35C. I also have never used "relays" before and have almost zero understanding on them. So if using them instead of the ceramic heater is the better option, I'm all ears mate

 

[mgill]

If I take this route will the cooling / heating effect work? I know it won't be as fast as using a ceramic heater but that is not a problem, just as long as it can reach the desired temperature. The temperature range I'm aiming for won't exceed 13-15C and 30-35C. I also have never used "relays" before and have almost zero understanding on them. So if using them instead of the ceramic heater is the better option, I'm all ears mate

thats the path i would go down. I would make sure the module does what it says (function 2 and function 3) Function 2 is your temperature difference default and function 3 is your timeout delay temperature difference is set to 0.5 degrees and compressor timeout is set to 3 minutes, these look like good values, it won't heat or cool if the temperature is within 0.5 degrees of your set point, and the minimum time within which it will switch from heating to cooling and vice versa is 3 minutes (should give enough time for the two sides of the peltier to stabilise to close to the same temperature.

I will draw up a quick schematic tomorrow and scan for you as to how you would hook it up... the whole system will have a fairly slow rate at which the temperature changes so you may find that you could adjust the function 2 and function 3 parameters to tune the system better.

 

[funkyyyy]

thats the path i would go down. I would make sure the module does what it says (function 2 and function 3) Function 2 is your temperature difference default and function 3 is your timeout delay temperature difference is set to 0.5 degrees and compressor timeout is set to 3 minutes, these look like good values, it won't heat or cool if the temperature is within 0.5 degrees of your set point, and the minimum time within which it will switch from heating to cooling and vice versa is 3 minutes (should give enough time for the two sides of the peltier to stabilise to close to the same temperature.

I will draw up a quick schematic tomorrow and scan for you as to how you would hook it up... the whole system will have a fairly slow rate at which the temperature changes so you may find that you could adjust the function 2 and function 3 parameters to tune the system better.

Thanks mate, I really appreciate it. I actually had been messing with Function 3 when I first fired up the temp controller and was scratching my head as to why the cooling output wasn't working (it was, just wouldn't turn on untill 4 minutes) .. I ended up rewiring the whole thing before I gave up and consulted the instructions. Ha. Glad to see it finally has a use, I look forward to seeing the diagram. I live right up the road from a brand new Jaycar. Slow temperature change isn't really an issue for me, just as long as it happens.

 

[mgill]

Thanks mate, I really appreciate it. I actually had been messing with Function 3 when I first fired up the temp controller and was scratching my head as to why the cooling output wasn't working (it was, just wouldn't turn on untill 4 minutes) .. I ended up rewiring the whole thing before I gave up and consulted the instructions. Ha. Glad to see it finally has a use, I look forward to seeing the diagram. I live right up the road from a brand new Jaycar. Slow temperature change isn't really an issue for me, just as long as it happens.

Nice and convenient then... I worked at a Jaycar for a few years when I was at uni so i tended to either do a lot of little projects like this or be involved in helping a lot of people with projects like this. Only downside is that trying to get help out of half the staff members there these days is very hard, either they don't know what they are talking about, or they aren't willing to divulge any information due to fear of liability.

 

[funkyyyy]

Nice and convenient then... I worked at a Jaycar for a few years when I was at uni so i tended to either do a lot of little projects like this or be involved in helping a lot of people with projects like this. Only downside is that trying to get help out of half the staff members there these days is very hard, either they don't know what they are talking about, or they aren't willing to divulge any information due to fear of liability.

I wouldn't mind a job there next year for my Gap year.. the shop we have is run by a few incompetent people who seem to always be playing with the remote control helicopters and what not. I refuse to ask for professional advice there after one of them tried to sell me thin guage wire that was rated at a MAXIMUM of 12.8V @ 6-8A and pass it off as 220VAC compliant, simply because he looked at the wiring diagram I had for the temp controller (Blue, brown and green for the N, L and E) and compared it to the colours he had on the 12v wiring. Rant over, anyway I have one more question before switching my project down this road.

I know the peltiers I have (rated at 60w) get VERY cold, how efficient will they be at transferring the heat from the hot side, through the large heatsink to the fans to blow this warmth into the cabinet? (Mind you, the dimensions are only 1365x545x150.. subtracking 300mm off of the length to house the electronics..

 

[mgill]

I wouldn't mind a job there next year for my Gap year.. the shop we have is run by a few incompetent people who seem to always be playing with the remote control helicopters and what not. I refuse to ask for professional advice there after one of them tried to sell me thin guage wire that was rated at a MAXIMUM of 12.8V @ 6-8A and pass it off as 220VAC compliant, simply because he looked at the wiring diagram I had for the temp controller (Blue, brown and green for the N, L and E) and compared it to the colours he had on the 12v wiring. Rant over, anyway I have one more question before switching my project down this road.

I know the peltiers I have (rated at 60w) get VERY cold, how efficient will they be at transferring the heat from the hot side, through the large heatsink to the fans to blow this warmth into the cabinet? (Mind you, the dimensions are only 1365x545x150.. subtracking 60mm off of the length to house the electronics..

With this solution you will only have one side transferring a temperature change into your cabinet. There is no specific hot or cold side to a peltier, the sides will be either hot or cold depending on which way you hook the voltage up to them. You can test this if you want, connect the peltier up to a 12V supply (red to red, black to black) see which side gets hot, make a note of it... now let the peltier cool down so the both sides are the same temperature (important as you don't really want to switch from heating to cooling if there is a large temperature difference between the two plates (hence your function 2 and 3 settings should take care of this). Once its has cooled to room temperature try changing the polarity red wire to black (negative) and black wire to red (positive). The side which was hot will now get cold. So all you will need to do is let the air blow in from one side of the peltier and exhaust the other side out into the room. The heating capacity will be greater than the cooling capacity of the peltier as the devices are not very efficient at cooling (low efficiency and conservation of energy means the energy will be lost through heat).
The effieciency of moving the temperature controlled air around will be pretty much the same whether it is heating or cooling so I wouldn't be too concerned about that. Only other downside is if you are using a thermal circuit breaker on the heatsink, you may want to put one on both heatsinks although I don't envisage they will reach these temperatures.

 

[funkyyyy]

With this solution you will only have one side transferring a temperature change into your cabinet. There is no specific hot or cold side to a peltier, the sides will be either hot or cold depending on which way you hook the voltage up to them. You can test this if you want, connect the peltier up to a 12V supply (red to red, black to black) see which side gets hot, make a note of it... now let the peltier cool down so the both sides are the same temperature (important as you don't really want to switch from heating to cooling if there is a large temperature difference between the two plates (hence your function 2 and 3 settings should take care of this). Once its has cooled to room temperature try changing the polarity red wire to black (negative) and black wire to red (positive). The side which was hot will now get cold. So all you will need to do is let the air blow in from one side of the peltier and exhaust the other side out into the room. The heating capacity will be greater than the cooling capacity of the peltier as the devices are not very efficient at cooling (low efficiency and conservation of energy means the energy will be lost through heat).
The effieciency of moving the temperature controlled air around will be pretty much the same whether it is heating or cooling so I wouldn't be too concerned about that. Only other downside is if you are using a thermal circuit breaker on the heatsink, you may want to put one on both heatsinks although I don't envisage they will reach these temperatures.

Yeah I get what you mean with the polarity, all I really need to find out is if the set up will say... heat the air to 30C and cool it to maybe 15-16C. Are these realistic figures for two 60w peltiers?

 

[mgill]

Yeah I get what you mean with the polarity, all I really need to find out is if the set up will say... heat the air to 30C and cool it to maybe 15-16C. Are these realistic figures for two 60w peltiers?

yep, easily achievable.

 

[funkyyyy]

yep, easily achievable.

Thanks for yourhelp bro, if/when you get around to the schematics, I look forward to seeing them / learning about how the relay works.

 

[dmerrick]

Yes and no, peltiers work on a temperature differential, so a 15 degree differential is well within the specs of even a small cell. However, your volume will be the determining factor, the air is going to be the downside, its bad as a heat mass. Not trying to rain on your parade, it will work, but don't look for any real efficiency.

And like Mgill said, they're polarity dependant, whixh is kinda cool if you want to do true temperature control, rather than just switch the positive you can swap polarity and go the other way.

 

[funkyyyy]

Yes and no, peltiers work on a temperature differential, so a 15 degree differential is well within the specs of even a small cell. However, your volume will be the determining factor, the air is going to be the downside, its bad as a heat mass. Not trying to rain on your parade, it will work, but don't look for any real efficiency.

And like Mgill said, they're polarity dependant, whixh is kinda cool if you want to do true temperature control, rather than just switch the positive you can swap polarity and go the other way.

Yeah I completely agree with you, well aware these little things are not going to be instantly heating my enclosure or heating any large space efficiently, but seeing as my space is relatively small and this is just a school (HSC) based project I am willing to settle for something that may not be super efficient, but works to an extent

 

[mgill]

Thanks for yourhelp bro, if/when you get around to the schematics, I look forward to seeing them / learning about how the relay works.

This should do the trick, the wiring of those relays doesn't quite match up with the ones available from Jaycar but they should have a picture on them which follows the attached relay format, if it doesn't take a snap of them and I will point out which wire is which (you gotta get it right as if you don't and you have the condition where both relays are in the off position they will try and short circuit the ATX power supply).

 

[funkyyyy]

This should do the trick, the wiring of those relays doesn't quite match up with the ones available from Jaycar but they should have a picture on them which follows the attached relay format, if it doesn't take a snap of them and I will point out which wire is which (you gotta get it right as if you don't and you have the condition where both relays are in the off position they will try and short circuit the ATX power supply).
View attachment 47312

I appreciate what you have done for me, I'm having limitations with understanding the whole diagram though. Does this mean I have to re-wire my temp controller unit? Or will this work directly out of the flat panel mount female sockets for cooling / heating. Sorry, I've never messed with diagrams like that. It's all a bit of a jumble for me ha.