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Forum Index : Electronics : A new controller circuit
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Thats very good work Len! Well written and good circuit diagram. Now we just need someone to build and test it. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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sparkey Senior Member  Joined: 15/06/2011 Location: AustraliaPosts: 819 |
i think i have all the parts except the "2n2700"but i have a huge collection of stripped out at/atx power supplys i have some vero and so i have mostly"irf fets i will have to mod the cct because i run 36 volt but i will build a version up in the next week sparkey...///...///actully if you could please mod the cct for forty volts to drop out and 28 volts to engauge that would make me verry appreiacte and if u want one built for glen i need to also have the cct for what voltages he requires...///.../// technicians do it with least resistance |
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| larny Guru  Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Sparkey, You will need a 24 Volt relay. I will need to know its coil resistance. One of the FETs that you have on hand should do the job. So if you would list a few of them & I'll check their suitability. Len |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
ok i can order any thing that altronics stocks/wes stocks/or jaycar///i would prefer altronics as i have credit with them....its just a simple phone order ....and for my own system which is 36 volts ..are you recomending a 24 volt relay...and if possible give me the cct mods to follow please ...regards sparkey....oh and i only have 25k trimpots but i dont see this being a problem///...///also the voltage of the regular is not really clear on the scem is that an 5-6-8-9 volt ??? and if worst comes to worst i have some 317t regs i could use... technicians do it with least resistance |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Sparkey, Yes, I suggested a 24 Volt relay. Yes, I'll post a revised circuit in a day or 2. 25 k pots are OK. You won't be able to use an IC Voltage Regulator for a 36 Volt system. I'll design a reg to suit using either an NPN transistor or an N channel MOSFET. The reg on the circuit I posted is 8 Volt - as in Glenn's original. But that is too low for a 36 Volt system. len |
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| davef Guru Joined: 14/05/2006 Location: New ZealandPosts: 499 |
*** You won't be able to use an IC Voltage Regulator for a 36 Volt system. *** 100Volt http://www.ti.com/product/tps7a4001 greater than 50Volt here Check National and Linear Technology for similar products. |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
i dont have any 25 turn trim pots i can prolly get then in 20 k as per cct i think that these would do the job better than htp trim pots as adjustment seem`s critical i can order these when i know what exactly i need to order and a "npn" transistor vreg cct sounds good tip 31 or something around there or some thing smaller like bc 640 //or bc327 ..someting in a to 92 pack seems that high currents are not needed for the maintaining of this cct also the 100n cap on the input v+ to the 339 is a monolithic fine or do you prefer a mkt///regards sparkey from the cct desribed bi guess glen is ysing twelve volts but maybe i dont know for shure i was going to devolop a simiar cct for my set up but dont get a lot of wind here and i have a 40volt 3 phase generator well it does not usually pump out more than ten amps in very high winds... technicians do it with least resistance |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
ok the relay i have picked out is 24v dcdpdt 10 amp and has a coil resistance of"640 ohms " ::pt/no is s4312::altronics and the mosfet i picked out is ::IRF830::: hope this helps ...regards sparkey:::also they have it twelve volt coil resistance of160 ohm:::max coil power for both is 900 mw......also i was thinking that a 1amp fast diode for the relay.... technicians do it with least resistance |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Thanks davef for the information about the high voltage regulators, I did not know they were available. However, Sparkey's comment about the LM317 inspired me to reconsider. Unlike other regulators, the LM317 does not have a ground pin. It has a maximum input to output differential of 40 volts, therefore it is suitable for this circuit since the differential will be a maximum of roughly 17 volt. Len |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Sparkey, 25 turn trim pots will be good for the purpose. Note my comment to davef above. You said you have a 40 Volt three phase alternator. I don't know anything about alternators in wind generators, but I know that the alternators in cars produce high voltage spikes that will destroy unprotected electronics. Do you or anyone else know whether wind alternators also produce such spikes? I buy my parts from Semtronics who are located in Nunawading Victoria. They are usually significantly cheaper than the two stores that you mentioned. However, they are only a small company, so they don't have the manpower to maintain a proper website. See www.semtronics.com.au & you'll see what I mean. But please don't judge the company by the web site. I hasten to add that I have no financial or other interest in the company. Their prices & the fact that I live about 3 km away is why I use them. They also stock some parts (eg. resistor networks) that the other 2 don't. The 24 V relay be suitable, provided that the contact rating is sufficient for your purpose. I don't know that part of the circuit, so I'll leave it to you. Virtually any diode will do to put across the relay. The only consideration is whether it can withstand the relay current & the 40 Volt supply. The 24 V relay will draw about 38 mA, so that is not a problem for most diodes. So use whatever you have on hand. eg. 1N4004, 1N4148, etc. I'll check the IFR830 later & report back. Len |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
i can get the "2n2700 " from altronics i just wasent shure that it woul still be sdequite with the 24 volt relay thatys all..regards sparkey...als my "qth - is melb broady"also i only use 1% resistors in general if that is a problem i can use 5% resistors where not noted as 1% resistors i take it that they are al 1/4 watt types...also is the 10 mfd cap a tant technicians do it with least resistance |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
You mean the 2N7000. It is quite adequate for the 24 V relay as the relay will draw about 38 mA & the 2N7000 has a 60 V maximum Vds, so 40 V is OK. I'm not sure what you mean by "als my "qth - is melb broady"" Obviously melb = Melbourne & presumably broady = Broadmeadows. But "qth" has me stumpted. 1% is better than 5%. I only labled R1 & R2 as 1% since they need to be as close to the correct values as possible in order to minimise the division error. The others can be 1% or 5%. Yes, 1/4 W will be adequate. If I find any that need to be greater, I'll put a note to that effect. Yes the 10 uF can be a tant, but I have to change the voltage regulator, so that may change. Len |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
ok cool will awaight for your cct ..."qth" =location...its ham talk ...sorry about my typing its a bit on the poor side as i have to type with one finger and sometimes get ahead of my self ....no i have a full set of fingers and thumbs,,... the out put of my generator is actully clipped it is suposed to be a 24 volt system that came with a charge shunt controller but i found that when it cut the shunt element in it put a huge load on the system and my inverter shut down every time as this was not a good idea i decided to go up to 36 volts on the battery bank a nd use two bridge rectifiers and make a three phase rectifier i find that this is suffishent... technicians do it with least resistance |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
and on another note i was thinking about replacing the relay with a bank of 2n3055`s either driven off of the relay or put directly into the cct...relays have the drwback of being always make/break connection`s and they have to be able to take that over the contacts the "ark" is a problem but if you were to introduce a bank of transistors to switch the load i think that would take a heap of load of the contacts and give it a much longer life span also you would be driving the transitors either to saturation or in a ste of non conductance ...in a nut shell "of or on" .... technicians do it with least resistance |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
I have never been a ham (at least not a radio ham) so I don't know the jargon. Yes, that is a good idea. But I need you to educate me on what the relay does so I can design a transistor equivalent. My assumptions (guesses) are:- When the wind is strong, you need to put a dummy load on the alternator to:- 1. Slow it down so it does not destroy itself mechanically. 2. Reduce the voltage so the batteries are not damaged by over charging. Is this correct? If so, what is the resistance of the dummy load, ie. how much current is switched into the load? Thoughts:- It would be better to use MOSFETs rather than the bipolar 2N3055. You said you have some of the IRF830 MOSFETs - how many? You don't need a relay if you use electronic switching. If your relay contacts were damaged by arcing, then that implies that there is an inductive spike when the contacts open. This is not surprising given that the alternator is inductive. So the contacts would need overvoltage protection to prevent erosion. The same applies to an electronic switch - even more so as it would be killed immediately by a spike. Len |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
the relay is switching dc for a start ..in my setup... it just switches the current on or off depending on the battery voltage "storage batts" ... thats all it does .... and the shunt i mentioned is built in to the controller which i do not use at all ..its a door stopper... as for the current comming out of my generator its rectified to around a max of 45volts....so it really does not matter about the transistors yet lets get something built then we can worry about other implications down the track...thank you technicians do it with least resistance |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
Sparkey, What I'm trying to understand is :- What is the point of the circuit? ie. the one was attached by Gizmo in his first post & my variant of it. What does the relay (in that circuit) do when it operates? Is it the relay that you mentioned above? Or are you talking about another relay that you have in your arrangement? I looked at the spec for the IRF830 & it will be suitable to drive the relay. Len |
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| sparkey Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 819 |
the relay connects the output from the generating equimpment weather it be solar or generator power to the batteries so as to charge then...yoyr modided cct alows that the batteries are being charged or not charged if the batteries are in a full charged stae as to what ever the pots are set to then this will govern the charging so that they are ot overcharged,,,also are you going to release a copy of the cct with the 317 reg and mods to make it viable for my 36 volt system.... technicians do it with least resistance |
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| larny Guru Joined: 31/10/2011 Location: AustraliaPosts: 346 |
I had assumed that the batteries were being float charged. But you appear to be saying that the charging is only switched on when the battery voltage falls to <28 Volt (in your case) & switched off when the voltage reaches 40 Volt. Is that correct? If so I'll draw a variant circuit for your 36 Volt system with a relay output. We can think about electronic switching at a later date. Len |
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| Gizmo Admin Group Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
No Sparky this type of circuit is best used as a dump controller. One important factor in using a wind turbine is the alternator/generator must remain loaded at all times. You should never let a wind turbine free wheel, because they will over speed, the output voltage will rise signicantly and there is the risk of mechanical damage. Solar cells are a different matter, its OK to open circuit them. So a dump controller works by draining off the excess power generated by the wind turbine. In Lens circuit, you would use the relay contacts to switch a dump load across the battery. This dump load will drain off a lot of power, keep the windmill spinning at normal speed, and stop the battery overcharging. You can also use the circuit as a diversion controller, using a set of changeover contacts in the relay. In that situation, the windmill output is fed either to the battery, OR, a dump load. Its a bit more complicated to set up, and there are dissadvantages to a diversion controller, including voltage spikes, mechanical loading, and less safety margin. With a dump controller, the output of the alternator is always loaded by the battery and occasionally also the dump load. This means no voltage spikes or wild AC to deal with. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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