I am trying to couple my air conditioner to a blower. I want the blower to start when the fan in the AC does. It is a 3 speed motor , has 5 wires, neuteral and black ( across the AC supply with an electrolytic cap between them) then yel,orange red , these three wires go to solenoids on the PC board.
I bought a 110V relay, thinking I could connect it between neutral and one of the three wires from the relay. It does work, but it takes about 3 seconds before the relay clicks on. I don't care about the 3 seconds but I am not really understanding how these three wires affect the motor's speed.
Between the black and white, with the capacitor between I measure about 170 Volts, I guessed that perhaps the cap is smoothing the sine wave of the AC current , or somehow playing games with my digital meter.
I get something close to 110 at all three wires from the solenoids irreguardless of which fan speed is used. well that isn't exactly true , I did notice the voltage very slowly dropping at some of these points, but after 5 mins was still pretty close to 110. perhaps the windings are not completely separated electrically and I am reading voltage which is present because it is fed back through the windings being interconnected?
I guess my main concern is that the windings of the relay aren't connected in such a way that it is loading up the little PC board, and I would like to understand better how the motor is being controlled by these relays. can anyone with a better understanding of motor control enlighten me ? I have a scope I could connect to better understand ( by seeing the waveform) if that would help, I assume the phase or lag of the power is being changed by the circutry or something but I don't really understand it.
Your posting is confusing! You don't say which motor you are talking about when you give colors and voltages, youdon't say what the votlage is on the AC motor, and are youtrying to connect it to the AC blower motor in the furnace or to the AC compressor mnotor. Try starting over and maybe someone wioll eb able to understand you better. Sorry,
sorry for the confusion. I have a window type air conditioner , and I am trying to add a blower to assist the fan in the AC unit because I am pushing the air through some ducting. The AC unit has a little control panel, circut board and three relays to run it's internal 3 speed fan.
I am trying to wire it so when the AC unit turns it's fan on, the added blower comes on at the same time. Since I didn't want to load down the existing circutry in the AC unit I am trying to use a relay to turn the extra blower on and off.
At first I thought it would be simple because I came to the (incorrect ) conclusion that the 3 speed fan would use a neutral and 3 run windings that wouuld be turned on to give 3 different speeds. I also assumed that at least one of these three wires would be hot all the time, so I planned to use the 110 AC power to the fan to power the coil in the relay. The contacts of the (added) relay would be used to turn the fan on and off, and that is a separate circut not to be concerned with.
When I went to install the relay , instead of one neutral and three hot wires, I found there was one neutral, and a black wire and they are also connected across an electrolytic cap. there are three additional wires that run from the fan to the three relays on the little circut board. ( so 5 wires to the 3 speed fan)
Correct me if I am wrong, I am trying to wrap my head around how the circut works, but I assume the black and white wires are supplying most of the current to the fan,and are used for start up, and the three relays are turning on and off resistors which somehow affect coils in the motor , perhaps switching in and out three different loads to affect the induction and capacitance ratio, thus affecting the speed of the fan. Take that with a pinch of salt as I am unsure exactly how this circut works. ( and so I am asking)
when I measured 170 volts across the black and neutral and saw 170 volts I was afraid to use those wires to power the coil of the relay as it is only rated for 120 or so. So instead I hooked the relay between one of the three colored wires and the neutral.
To my surprise all three of these wires have something close to 110 and the relay works the way I wanted if it is hooked between neutral and any of these three wires. There is a delay of about 3 seconds in the relay being triggered. It appears to me that the fan is starting by using only the black and white wires , then the electronics come into play after this delay, and are switching on one of the 3 relays (depending on which speed is set) on the circut board to affect the speed of the fan.
I origionally thought the three wires from the relays were supplying most of the current , but I think I am wrong about that.
So if my assumption is correct , then adding the coil into the circut of any of these three wires probably affects one of the fan speeds slightly because it does add in the resistance, inductance and power draw of the holding coil of the relay to the circut run by the little board.
I think having the relay connected here may be changing one of the fan speeds slightly. I don't know if this is potentially damaging to the fan in the AC unit or it's little circut board. I will probably run the unit with it's fan on full speed most of the time that it is being used.
someone I discussed this with said i could buy a "voltage sensing relay" and that it could use only the neutral wire for it's trigger. I asked at the electronics store where I bought the 110 V relay but they hadn't heard of such a device.
So to sum up , my question is , is it ok hooked up like this ? is the load of the coil in the relay enough to damage anything?
If that's not clear just ask me to rephrase anything, Again sorry if my origional post wasn't well worded.
sorry for the confusion. I have a window type air conditioner , and I am trying to add a blower to assist the fan in the AC unit because I am pushing the air through some ducting. The AC unit has a little control panel, circut board and three relays to run it's internal 3 speed fan.
I am trying to wire it so when the AC unit turns it's fan on, the added blower comes on at the same time. Since I didn't want to load down the existing circutry in the AC unit I am trying to use a relay to turn the extra blower on and off.
At first I thought it would be simple because I came to the (incorrect ) conclusion that the 3 speed fan would use a neutral and
3 run windings that wouuld be turned on to give 3 different speeds. I also assumed that at least one of these three wires would be hot all the time, so I planned to use the 110 AC power to the fan to power the coil in the relay. The contacts of the (added) relay would be used to turn the added blower on and off, and that is a separate circut not to be concerned with.
When I went to install the relay (inside the AC unit) , instead of one neutral and three hot wires, as I had immagined, I found there was one neutral, and a black wire and they are also connected across an electrolytic cap. there are three additional wires that run from the fan to the three relays on the little circut board. ( so 5 wires to the 3 speed fan)
Correct me if I am wrong, I am trying to wrap my head around how the circut works, but I assume the black and white wires are supplying most of the current to the fan,and are used for start up, and the three relays are turning on and off resistors which somehow affect coils in the motor , perhaps switching in and out three different loads to affect the induction and capacitance ratio, thus affecting the speed of the fan. Take that with a pinch of salt as I am unsure exactly how this circut works. ( and so I am asking)
when I measured 170 volts across the black and neutral and saw 170 volts I was afraid to use those wires to power the coil of the relay as it is only rated for 120 or so. So instead I hooked the relay between one of the three colored wires and the neutral.
To my surprise all three of these wires have something close to 110 and the relay works the way I wanted if it is hooked between neutral and any of these three wires. There is a delay of about 3 seconds in the relay being triggered. It appears to me that the fan is starting by using only the black and white wires , then the electronics come into play after this delay, and are switching on one of the 3 relays (depending on which speed is set) on the circut board to affect the speed of the fan.
I origionally thought the three wires from the relays were supplying most of the current , but I think I am wrong about that.
So if my assumption is correct , then adding the coil into the circut of any of these three wires probably affects one of the fan speeds slightly because it does add in the resistance, inductance and power draw of the holding coil of the relay to the circut run by the little board.
I think having the relay connected here may be changing one of the fan speeds slightly. I don't know if this is potentially damaging to the fan in the AC unit or it's little circut board. I will probably run the unit with it's fan on full speed most of the time that it is being used.
Someone I discussed this with said i could buy a "voltage sensing relay" and that it could use only the neutral wire for it's trigger. I asked at the electronics store where I bought the 110 V relay but they hadn't heard of such a device.
So to sum up , my question is , is it ok hooked up like this ? is the load of the coil in the relay enough to damage anything?
If that's not clear just ask me to rephrase anything, Again sorry if my origional post wasn't well worded.
Isn't there a schematic inside the unit? The AC for the fan motor goes to the speed selector first, through the motor, then to neutral.
It sounds like you are trying to connect the relay to the compressor motor, which is harder, since there are start and run capacitors involved. You should just wire the relay so the booster fan runs whenever the A/C is turned on.
--
http://improve-usenet.org/index.html
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
Sporadic E is the Earth\'s aluminum foil beanie for the \'global warming\'
sheep.
The OP did't say if the AC was 120 or 240V. Let's assume 120V AC input. Depending on how many poles in the 3-speed motor, when there is 120V across the active winding, there may be a higher voltage measured across the unused windings that are not actually connected to the power line. The OP need to connect his 120V-input relay to the thermostat, before the three speed selection/switch gets involved.
The cap is a multi section can style cap. some of it is used for the compressor. I will have to read the label again to see if it is polarized. Yes there is a tiny schematic , but not info on it to show how the fan motor speed control works, just the wiring layout up to the PCB.
I think the black and neutral , which are hooked across the electrolytic and provide startup and most of the power to the motor. The three relays power some separate coils in the motor which are being switched in and out to affect speed. I think these coils are hooked in series , which is why I detected voltage at all three wires leading to solenoids all the time.
In the end I did use one of these connections for my added solenoid. ( and the neutral) It starts the blower about 3 seconds after the AC's fan comes on. I don't see any issues with this so I will leave it at that. I ran a couple of wires from the relay contacts to run the blower and it seems ok.
Thanks for the help and sorry if the post was confusing. phil
Depending upon how you set this up, it may result in high stress on the cooling system. The blower fan in the air conditioner and the cooling system are closely matched.
Each wire represents one fan speed. Each wire powers a different set of windings in the A/C fan motor. The typical color coding I've seen is black for HIGH, blue for MEDIUM and red for LOW. The voltage on each hot wire and the neutral will not usually differ...they should read line voltage (110/220) when energized.
The relays on the board simply turn on the desired speed. I'll bet the air conditioner you have has electronic controls. If so, a microcontroller will control the relays based on the buttons you press.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.