On Mon, 06 May 2013 12:01:44 -0400, Uncle Steve wrote:> Back again for some more abuse. > > I'm building a 12V battery charger that will be controlled by a small > low-power microcontroller. I've not yet hooked up the microcontroller, > but most of the code is written and I'm trying to finalize the charger > electronics before I hook it up. > > The circuit is very simple. An 18V 2A transformer, a bridge rectifier, > and filter capacitor feeds a main power rail. A 5V regulator produces a > few mA for the microcontroller, which I won't show here. The charger is > more or less as follows, though I will leave out the resistor/divider > taps which hook up to the ADC channels on the micro. > > > +18VDC ---------------------------+ > Q1 c e | D1 R1 > -----\_/--------->|----\/\/\--------+12(batt) > b| | > +------+ | > | | +--+----------+ > / Q2 e\_/c | > R1 \ |b | > / | e |c Q3 > \ +--\/\/\------\_/ > | R2 |b > | | R3 SW1 > LED1 \_/ +--\/\/\-- \-- +5V > --- > | > | > GND --------------+------------------------------------ GND(batt) > > > Q1 - MJE3055 > D1 - 1N4004 > R1 - .5 5W > > Q2 - BC557 > R2 - 200K > > Q3 - 2N2222 > R3 - 1K > > > The microcontroller will strobe R3 with PCM at about 488HZ with a duty > cycle dependant on the charge profile. R1 is the sense resistor and > permits measuring instantaneous charge current. I've got the battery > attached and can watch the voltage rise (and settle) as I manually > engage a switch attached as shown. The battery voltage as it came from > Wallmart was about 12.7V. Charge current with this circuit is 1.4A at > this point in its charge cycle. The heat-sink gets rather warm, but it > isn't all that big and I'm going to target 3 or 4A as the peak charge > current so I'll probably substitute a TO-3 package with a much beefier > heat-sink when I put the project in an enclosure. > > So far, so good. The output of Q1 shows .6V ripple. Attaching my scope > to the base of Q1 shows an idle (SW off) voltage of 16mV and a 120Hz > signal with a 70mVpp with a duty cycle of 17%. I'm not exactly sure > where this signal is coming from, although its frequency suggests a > causal relationship with the AC mains. There does not appear to be any > ripple on the 5V rail, but my scope isn't good enough to really zoom in > on it. > > The other side of the coin is that the Q2/Q3 network seems to be rather > sensitive. When I pass my hand over the breadboard the distortion > described above doubles and I can get an amplitude of 1V on that > distortion by standing up suddenly while sitting in front of the idle > circuit. It is difficult to say what is happening because I can double > the distortion by attaching the scope to a wall-wart USB charger, and I > know I haven't yet calibrated the scope all that well either. (Scope > shows 4.5V from the 5V regulator.) But the fact that I can affect the > circuit just by moving things in the general vicinity is, um, rather > shocking. > > Besides installing the circuit in a metal case, are there any easy > solutions to fix that 16mV idle voltage? Should I just change the BC557 > to a 2n2222 and work out how many of what kind of resistors I need to > supply the 3055 with the mA it needs to dump several amps into the > battery? I like this version because it is easy to set up and has a low > part count, but I'd really like to get rid of the noise and the > sensitivity to movement.Start a new thread! This isn't even remotely related to fan motors! -- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
Whole house fan motor
Started by ●May 5, 2013
Reply by ●May 6, 20132013-05-06
Reply by ●May 6, 20132013-05-06
On 5/6/2013 11:01 AM, Uncle Steve wrote:> Back again for some more abuse.Where's Phil when somebody really deserves abuse? Mikek> +18VDC ---------------------------+ > Q1 c e | D1 R1 > -----\_/--------->|----\/\/\--------+12(batt) > b| | > +------+ | > | | +--+----------+ > / Q2 e\_/c | > R1 \ |b | > / | e |c Q3 > \ +--\/\/\------\_/ > | R2 |b > | | R3 SW1 > LED1 \_/ +--\/\/\-- \-- +5V > --- > | > | > GND --------------+------------------------------------ GND(batt) > >
Reply by ●May 6, 20132013-05-06
On May 6, 3:35=A0pm, Tim Wescott <t...@seemywebsite.com> wrote:> On Mon, 06 May 2013 12:01:44 -0400, Uncle Steve wrote: > > Back again for some more abuse. > > > I'm building a 12V battery charger that will be controlled by a small > > low-power microcontroller. =A0I've not yet hooked up the microcontrolle=r,> > but most of the code is written and I'm trying to finalize the charger > > electronics before I hook it up. > > > The circuit is very simple. =A0An 18V 2A transformer, a bridge rectifie=r,> > and filter capacitor feeds a main power rail. =A0A 5V regulator produce=s a> > few mA for the microcontroller, which I won't show here. =A0The charger=is> > more or less as follows, though I will leave out the resistor/divider > > taps which hook up to the ADC channels on the micro. > > > =A0+18VDC ---------------------------+ > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Q1 c =A0 e =A0 | =A0 ==A0D1 =A0 =A0 R1> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0-----\_/--------->|----\=/\/\--------+12(batt)> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 b| =A0 =A0 | > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 +------+ =A0 =A0 | > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0 =A0| =A0+--+-----=-----+> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 / =A0Q2 e\_/c =A0 =A0 =A0 ==A0 =A0 =A0 |> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0R1 \ =A0 =A0 =A0 |b =A0 =A0 =A0 ==A0 =A0 =A0 =A0|> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 / =A0 =A0 =A0 | =A0 =A0 =A0==A0 =A0 =A0e =A0|c Q3> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 \ =A0 =A0 =A0 +--\/\/\-----=-\_/> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0 =A0 =A0 =A0 R2 ==A0 =A0 =A0 =A0 |b> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | =A0 =A0 =A0 =A0 =A0 =A0 ==A0 =A0 =A0 =A0 =A0| =A0 R3 =A0 =A0 SW1> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 LED1 \_/ =A0 =A0 =A0 =A0 =A0 =A0 =A0 ==A0 =A0 =A0 +--\/\/\-- \-- +5V> > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0--- > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | > > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 | > > =A0GND =A0 =A0--------------+------------------------------------ GND(b=att)> > > Q1 - MJE3055 > > D1 - 1N4004 > > R1 - .5 5W > > > Q2 - BC557 > > R2 - 200K > > > Q3 - 2N2222 > > R3 - 1K > > > The microcontroller will strobe R3 with PCM at about 488HZ with a duty > > cycle dependant on the charge profile. =A0R1 is the sense resistor and > > permits measuring instantaneous charge current. =A0I've got the battery > > attached and can watch the voltage rise (and settle) as I manually > > engage a switch attached as shown. =A0The battery voltage as it came fr=om> > Wallmart was about 12.7V. =A0Charge current with this circuit is 1.4A a=t> > this point in its charge cycle. =A0The heat-sink gets rather warm, but =it> > isn't all that big and I'm going to target 3 or 4A as the peak charge > > current so I'll probably substitute a TO-3 package with a much beefier > > heat-sink when I put the project in an enclosure. > > > So far, so good. =A0The output of Q1 shows .6V ripple. =A0Attaching my =scope> > to the base of Q1 shows an idle (SW off) voltage of 16mV and a 120Hz > > signal with a 70mVpp with a duty cycle of 17%. =A0I'm not exactly sure > > where this signal is coming from, although its frequency suggests a > > causal relationship with the AC mains. =A0There does not appear to be a=ny> > ripple on the 5V rail, but my scope isn't good enough to really zoom in > > on it. > > > The other side of the coin is that the Q2/Q3 network seems to be rather > > sensitive. =A0When I pass my hand over the breadboard the distortion > > described above doubles and I can get an amplitude of 1V on that > > distortion by standing up suddenly while sitting in front of the idle > > circuit. =A0It is difficult to say what is happening because I can doub=le> > the distortion by attaching the scope to a wall-wart USB charger, and I > > know I haven't yet calibrated the scope all that well either. =A0(Scope > > shows 4.5V from the 5V regulator.) =A0But the fact that I can affect th=e> > circuit just by moving things in the general vicinity is, um, rather > > shocking. > > > Besides installing the circuit in a metal case, are there any easy > > solutions to fix that 16mV idle voltage? =A0Should I just change the BC=557> > to a 2n2222 and work out how many of what kind of resistors I need to > > supply the 3055 with the mA it needs to dump several amps into the > > battery? =A0I like this version because it is easy to set up and has a =low> > part count, but I'd really like to get rid of the noise and the > > sensitivity to movement. > > Start a new thread! =A0This isn't even remotely related to fan motors! > > -- > My liberal friends think I'm a conservative kook. > My conservative friends think I'm a liberal kook. > Why am I not happy that they have found common ground? > > Tim Wescott, Communications, Control, Circuits & Softwarehttp://www.wesco=ttdesign.com- Hide quoted text -> > - Show quoted text -Yes a new thread is in order. The middle of the circuit is weird. (at least to me.) Your moving hand thing is a sure sign of electrostatic pickup. George H.
Reply by ●May 6, 20132013-05-06
telengard wrote:> On May 5, 8:12 pm, Jamie > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote: > >>telengard wrote: >> >>>Just recently purchased a house and it has a whole house fan. >>>Unfortunately, the folks who installed the A/C disconnected the >>>motorized louvers to get into the crawl space a couple months ago and >>>I'm not sure exactly how it was wired. In the crawl space there is a >>>black (which had a wire nut on it) and bare wire and a white wire >>>which looks like it was curled up to not use it (it is not stripped). >>>The motor on the louvers has 2 black wires and a green wire. >>>Unfortunately, I could not find any documentation on the motor. We >>>have 2 separate switches so the louvers are independently controlled. >> >>>Just wondering what the wires on the motor are. The motor is a Dayton >>>Motor Shutter Model 2C904 115V 60Hz. >> >>>Any info greatly appreciated. >> >> the two wires are your 120 volt AC lines from the motor.. >> >> in your case, you can connect the black wires from the motor to >>the white and black wire that is capped off.. >> >> the green wire from the motor is the ground which is connected to the >>bare wire you see.. >> >> P.S. >> since there is a wire nut on the black wire, this tells me it could >>be alive or at some point may come alive... >> I would first kill the circuit that supplies that before attaching the >>last black lead from the motor to that one. >> >> Also, this appears to be a single direction motor, this tells me that >>the shutter drive must not have a stop on it or it just keeps going >>around and around.. Most likely has an eccentric wheel or a wheel with >>an offset swing arm on it. >> >>Jamie > > > Hi Jamie, > > Thanks for the info, I have been shutting off the breaker when working > with this. I guess I'm surprised that the white wire would be used, I > guess the A/C guys may have just twisted it up for safety. That must > be the missing piece, I had tested both blacks to the one black > (assuming the white was was wrapped up as it was not used). > > And yes, the motor has some kind of arm attached to it w/ a spring.The white wire is the other power wire you need to connect one of the black wires on the motor to. THe only reason it is not protected via a wire nut is because that wire ends up being the low side of the circuit, which should be near 0 volts. But don't take any chances to think it is just a ground wire, just because it does connect to the ground back to subpanel. Jamie
Reply by ●May 6, 20132013-05-06
Uncle Steve wrote:> Back again for some more abuse. > > I'm building a 12V battery charger that will be controlled by a small > low-power microcontroller. I've not yet hooked up the > microcontroller, but most of the code is written and I'm trying to > finalize the charger electronics before I hook it up. > > The circuit is very simple. An 18V 2A transformer, a bridge > rectifier, and filter capacitor feeds a main power rail. A 5V > regulator produces a few mA for the microcontroller, which I won't show > here. The charger is more or less as follows, though I will leave out > the resistor/divider taps which hook up to the ADC channels on the > micro. > > > +18VDC ---------------------------+ > Q1 c e | D1 R1 > -----\_/--------->|----\/\/\--------+12(batt) > b| | > +------+ | > | | +--+----------+ > / Q2 e\_/c | > R1 \ |b | > / | e |c Q3 > \ +--\/\/\------\_/ > | R2 |b > | | R3 SW1 > LED1 \_/ +--\/\/\-- \-- +5V > --- > | > | > GND --------------+------------------------------------ GND(batt) > > > Q1 - MJE3055 > D1 - 1N4004 > R1 - .5 5W > > Q2 - BC557 > R2 - 200K > > Q3 - 2N2222 > R3 - 1K > > > The microcontroller will strobe R3 with PCM at about 488HZ with a duty > cycle dependant on the charge profile. R1 is the sense resistor and > permits measuring instantaneous charge current. I've got the battery > attached and can watch the voltage rise (and settle) as I manually > engage a switch attached as shown. The battery voltage as it came > from Wallmart was about 12.7V. Charge current with this circuit > is 1.4A at this point in its charge cycle. The heat-sink gets rather > warm, but it isn't all that big and I'm going to target 3 or 4A as the > peak charge current so I'll probably substitute a TO-3 package with a > much beefier heat-sink when I put the project in an enclosure. > > So far, so good. The output of Q1 shows .6V ripple. Attaching my > scope to the base of Q1 shows an idle (SW off) voltage of 16mV and a > 120Hz signal with a 70mVpp with a duty cycle of 17%. I'm not exactly > sure where this signal is coming from, although its frequency suggests > a causal relationship with the AC mains. There does not appear to be > any ripple on the 5V rail, but my scope isn't good enough to really > zoom in on it. > > The other side of the coin is that the Q2/Q3 network seems to be > rather sensitive. When I pass my hand over the breadboard the > distortion described above doubles and I can get an amplitude of 1V on > that distortion by standing up suddenly while sitting in front of the > idle circuit. It is difficult to say what is happening because I can > double the distortion by attaching the scope to a wall-wart USB > charger, and I know I haven't yet calibrated the scope all that well > either. (Scope shows 4.5V from the 5V regulator.) But the fact > that I can affect the circuit just by moving things in the general > vicinity is, um, rather shocking. > > Besides installing the circuit in a metal case, are there any easy > solutions to fix that 16mV idle voltage? Should I just change the > BC557 to a 2n2222 and work out how many of what kind of resistors I > need to supply the 3055 with the mA it needs to dump several amps into > the battery? I like this version because it is easy to set up and has > a low part count, but I'd really like to get rid of the noise and the > sensitivity to movement. > > > Regards, > > Uncle Steve >Kind of curious how that LED is handling the current when you only have a .5 ohm R feeding it? Even if that bias on the base was current limited, you'll be suppressing the voltage to the battery no more than what the LED forward voltage is plus the 0.650 drop from the base and emitter. As for the noise you maybe seeing, it's possible you are picking that up because of the wires hanging all over the place. You most likely have lights with ballast circuits in them, they can generate noise, putting your hands over the circuit is just using your body to convey the noise closer. bjts are grate for acting as R.F. detectors... Jamie
Reply by ●May 6, 20132013-05-06
On Mon, 06 May 2013 12:01:44 -0400, Uncle Steve <stevet810@gmail.com> wrote:>Back again for some more abuse. > >I'm building a 12V battery charger that will be controlled by a small >low-power microcontroller. I've not yet hooked up the >microcontroller, but most of the code is written and I'm trying to >finalize the charger electronics before I hook it up. >[snip] How is the charger "controlled"? Do you mean that the output CURRENT from the charger will be a function of the "duty-cycle" from the micro-controller? Or do you have some other algorithm in mind? ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●May 6, 20132013-05-06
On Mon, May 06, 2013 at 06:59:01PM -0700, Jim Thompson wrote:> On Mon, 06 May 2013 12:01:44 -0400, Uncle Steve <stevet810@gmail.com> > wrote: > > >Back again for some more abuse. > > > >I'm building a 12V battery charger that will be controlled by a small > >low-power microcontroller. I've not yet hooked up the > >microcontroller, but most of the code is written and I'm trying to > >finalize the charger electronics before I hook it up. > > > [snip] > > How is the charger "controlled"? > > Do you mean that the output CURRENT from the charger will be a > function of the "duty-cycle" from the micro-controller?The average current, yes.> Or do you have some other algorithm in mind?I've used a similar technique in other circumstances. In this instance the ADC measurements of the carger circuit will determine how much energy will be dumped into the battery at any given time, again /on average/. Lead acid battery chemistry has significant hysteresis, so I do not at this time expect any major problems with this strategy. The instantaneous current at any time will be limited by the power supply, so it's not as if there will be tens of amps rushing the battery while the power transistor is turned on. Regards, Uncle Steve -- There should be a special word in the English language to identify people who create problems and then turn around and offer up their own tailor-made bogus non-solutions designed to completely avoid the root causes of the situation under consideration. 'Traitor' might be a good choice, but lacks the requisite specificity. One of the problems with contemporary English is it lacks many such words that would otherwise categorically identify certain kinds of person, place, or thing -- making it difficult or impossible to think analytically about such objects. These shortcomings of the English lexicon are representative of Orwellian linguistics at work in the real world.
Reply by ●May 6, 20132013-05-06
On Mon, 06 May 2013 22:16:14 -0400, Uncle Steve <stevet810@gmail.com> wrote:>On Mon, May 06, 2013 at 06:59:01PM -0700, Jim Thompson wrote: >> On Mon, 06 May 2013 12:01:44 -0400, Uncle Steve <stevet810@gmail.com> >> wrote: >> >> >Back again for some more abuse. >> > >> >I'm building a 12V battery charger that will be controlled by a small >> >low-power microcontroller. I've not yet hooked up the >> >microcontroller, but most of the code is written and I'm trying to >> >finalize the charger electronics before I hook it up. >> > >> [snip] >> >> How is the charger "controlled"? >> >> Do you mean that the output CURRENT from the charger will be a >> function of the "duty-cycle" from the micro-controller? > >The average current, yes. > >> Or do you have some other algorithm in mind? > >I've used a similar technique in other circumstances. In this >instance the ADC measurements of the carger circuit will determine how >much energy will be dumped into the battery at any given time, again >/on average/. Lead acid battery chemistry has significant hysteresis, >so I do not at this time expect any major problems with this strategy. >The instantaneous current at any time will be limited by the power >supply, so it's not as if there will be tens of amps rushing the >battery while the power transistor is turned on. > > >Regards, > >Uncle SteveHow about something like this... http://www.analog-innovations.com/SED/ChargerForUncleSteve.pdf ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●May 7, 20132013-05-07
On Mon, May 06, 2013 at 06:44:23PM -0400, Jamie wrote:> Kind of curious how that LED is handling the current when you only have > a .5 ohm R feeding it? Even if that bias on the base was currentThat's the other R1. The R1 attached to the LED is 2.2K, a mistake I updated in a later post.> limited, you'll be suppressing the voltage to the battery no more than > what the LED forward voltage is plus the 0.650 drop from the base and > emitter. > > As for the noise you maybe seeing, it's possible you are picking that > up because of the wires hanging all over the place. You most likely have > lights with ballast circuits in them, they can generate noise, putting > your hands over the circuit is just using your body to convey the noise > closer.I have CFL lights, a stereo, a HDTV, several laptop computers, 4G phone, oh, and there's a single fluorescent tube in the bathroom. but the signal I'm seeing at the base of Q1 (NPN) is 60/120 Hz at 70mVpp (depending on how the scope sees it) on 16V DC, and I'm only seeing the positive side of the ripple. At power on, the spikes are much larger and fall over a couple of seconds to the stated amplitude. The transformer that is powering everything has no regulator, only a bridge rectifier and a 470uF filter cap. There may be some ripple but it must be very close to the resolution that my scope LCD can display. Open-circuit voltage is 26V, which quickly drops to 19V with a 1.6A load, so I'm wondering if a 7818 regulator would clear things up, but that would necessarily introduce a different problem.> bjts are grate for acting as R.F. detectors...The wires hooking up anything related to Q2/Q3 are no more than four inches long; everything else (other than the 5V supply rail for the uC) is attached to the 18V rail. I can tighten things up on the breadboard a bit, but if RF is getting to the transistors through their 1" leads there's little I can do about that. ISR that antennas are sensitive to wavelength as a function of lengths, and VLF antennas are measured in the hundreds of meters. Obviously IANAEE, and I know much less about antennas than I do about transistors, which is next to zilch. Regards, Uncle Steve -- There should be a special word in the English language to identify people who create problems and then turn around and offer up their own tailor-made bogus non-solutions designed to completely avoid the root causes of the situation under consideration. 'Traitor' might be a good choice, but lacks the requisite specificity. One of the problems with contemporary English is it lacks many such words that would otherwise categorically identify certain kinds of person, place, or thing -- making it difficult or impossible to think analytically about such objects. These shortcomings of the English lexicon are representative of Orwellian linguistics at work in the real world.
Reply by ●May 7, 20132013-05-07
Jamie wrote:> > telengard wrote: > > > On May 5, 8:12 pm, Jamie > > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote: > > > >>telengard wrote: > >> > >>>Just recently purchased a house and it has a whole house fan. > >>>Unfortunately, the folks who installed the A/C disconnected the > >>>motorized louvers to get into the crawl space a couple months ago and > >>>I'm not sure exactly how it was wired. In the crawl space there is a > >>>black (which had a wire nut on it) and bare wire and a white wire > >>>which looks like it was curled up to not use it (it is not stripped). > >>>The motor on the louvers has 2 black wires and a green wire. > >>>Unfortunately, I could not find any documentation on the motor. We > >>>have 2 separate switches so the louvers are independently controlled. > >> > >>>Just wondering what the wires on the motor are. The motor is a Dayton > >>>Motor Shutter Model 2C904 115V 60Hz. > >> > >>>Any info greatly appreciated. > >> > >> the two wires are your 120 volt AC lines from the motor.. > >> > >> in your case, you can connect the black wires from the motor to > >>the white and black wire that is capped off.. > >> > >> the green wire from the motor is the ground which is connected to the > >>bare wire you see.. > >> > >> P.S. > >> since there is a wire nut on the black wire, this tells me it could > >>be alive or at some point may come alive... > >> I would first kill the circuit that supplies that before attaching the > >>last black lead from the motor to that one. > >> > >> Also, this appears to be a single direction motor, this tells me that > >>the shutter drive must not have a stop on it or it just keeps going > >>around and around.. Most likely has an eccentric wheel or a wheel with > >>an offset swing arm on it. > >> > >>Jamie > > > > > > Hi Jamie, > > > > Thanks for the info, I have been shutting off the breaker when working > > with this. I guess I'm surprised that the white wire would be used, I > > guess the A/C guys may have just twisted it up for safety. That must > > be the missing piece, I had tested both blacks to the one black > > (assuming the white was was wrapped up as it was not used). > > > > And yes, the motor has some kind of arm attached to it w/ a spring. > The white wire is the other power wire you need to connect one of the > black wires on the motor to. > > The only reason it is not protected via a wire nut is because that > wire ends up being the low side of the circuit, which should be near > 0 volts. But don't take any chances to think it is just a ground wire, > just because it does connect to the ground back to subpanel.No, it doesn't. It connects to the Neutral, if the circuit is 120 VAC. It may be the other side of a 240 VAC circuit, if it's not wired to code.
