Whole house fan motor

[telengard]

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.

 

[telengard]

  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.

 

[Jamie]

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

 

[Tom Biasi]

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.

When you say the white wire was wrapped, is it wrapped with black tape?
If so it is probably a hot from the switch.

 

[[email protected]]

When you say the white wire was wrapped, is it wrapped with black tape?

If so it is probably a hot from the switch.

Sorry, I should have been more precise. The white wire was not stripped, was not in a wire nut, and was coiled up whereas the other 2 wires were straight (for lack of a better term). In other words, it looked like it wasn'tbeing used, or this was done to prevent a short or something, although I would have thought having the dangling black and bare would be just as bad.

 

[amdx]

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.
exti

First I'd like to say, I had a home with a whole house fan, and it was
great on those summer nights in Michigan. Just crack the windows in the
room about 4" and turn on the fan. Great breeze comes through.

There may be a reason it is disconnected ( doesn't work?). I would
first verify operation of the louver controller. I have enough extension
cords around that I would just wire a cord to it and plug it in. If it
opens, unplug it and see if it closes.
If it works, I would then follow the wiring from the motor and see if
there is a parallel wiring connection that could be connected to the
louver controller.
Here is a link that gave me the little I know about electric louvers.

Please get your own understanding, before attempting repair.

(istr, my louvers were opened by the draft that came through)
From what I read, the louver controller opens with power on and closes
when power is removed.
The second link refers to the replacement model that Grainger
recommends for your unit.

http://www.google.com/url?sa=t&rct=...deP1yRQ-Xip_Rzw&bvm=bv.45960087,d.eWU&cad=rja
http://www.google.com/url?sa=t&rct=...deP1yRQ-Xip_Rzw&bvm=bv.45960087,d.eWU&cad=rja

http://www.google.com/url?sa=t&rct=...=ntWF2coocobBbvKJXyNgSw&bvm=bv.45960087,d.eWU

http://www.google.com/url?sa=t&rct=...=ntWF2coocobBbvKJXyNgSw&bvm=bv.45960087,d.eWU

 

[amdx]

Back again for some more abuse.

Where's Phil when somebody really deserves abuse?
Mikek

 

[George Herold]

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 & Softwarehttp://www.wescottdesign.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.

 

[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

 

[Jamie]

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

 

[ehsjr]

36:21 -0400, Uncle Steve <[email protected]>
wrote:

57, Jim Thompson wrote:
[snip]

How about something like this...

http://www.analog-innovations.com/SED/ChargerForUncleSteve.pdf

...Jim Thompson

If Uncle is using a micro to control it, why not just control a mosfet
with the PWM output ???

I have the app notes for the LM338 and such, which show simple charger
circuits like that, but the fact of the matter is I have a couple of
3055s and this project is as much about learning some basics as it is
about charging a battery. For my requirements it is easier to use
what I have on hand than try to select among parts that I don't really
understand. If there were a fundamental reason why the 3055 is bad
for this application I might consider a mosfet, but I don't see why I
should bother.

Regards,

Uncle Steve

The 3055 has a minimum beta of 20 at 4 Amps, which you spoke of at one
point in this thread, which means the base current that must be
supplied is 200mA... not a big deal EXCEPT the driving device will see
considerable dissipation.

I'm starting to appreciate these factors. Yet, after removing the
4004 diode as superfluous and changing the .5 ohm sense resistor to
.1 ohms, I'm seeing 3A output which is pretty much the capacity of the
power supply. The 3055 runs cooler as well; not sure what that means.

Now I have to use an op-amp comparator to measure the current to get
decent resolution.

You ought to go buy the TO-3 version of the LM317 for the circuit I
suggested and avoid the magic smoke ;-)

The literature doesn't specify the switching frequency, rise time,
etc. for that part.


Regards,

Uncle Steve

I'm curious why you need to "switch" it? Isn't your only concern the
_average_ current, as determined by the PWM?

All you need is a low-pass R/C between the micro and the base of Q1
(as noted in the text box on the schematic).

I'll run a simulation of that and repost later (under this same link).

http://www.analog-innovations.com/SED/ChargerForUncleSteve.pdf

You're probably correct, except the rating of the LM317 is half of
what I need.

I would urge you to follow JT's advice. Build his circuit.

It is easy to add a pass element to get higher current later on.
Here's an example diagram to give you an idea how it's done:


MJ2955
Vin ---+----> ------------------+-----------> Vout
| e\ /c |
[3R] --- |
| | ----- |
+------+---Vin|LM317|Vout---+-------+
| ----- | |
| Adj [240R] |
| | | |
| +----------+ |
| | |
[.22uF] / [.1uF]
| \ |
| 5K /<---+ |
| \ | |
| / | |
| | | |
Gnd ----------+---------+----+-------------+


Current drawn from the 317 causes a voltage drop across the
3 ohm resistor. When that voltage drop is below about .6 volts,
the 2955 conducts no e-c current. When the voltage drop rises
to about .6 volts the 2955 begins to conduct e-c current. The
more current drawn by the load, the greater the e-c current.
The e-c current passes around (not through) the 317 so the 2955
is called a pass element or pass transistor.

You can also do it with your 3055, but you need an inverting
stage to its base. See "High Current Adjustable Regulator"
diagram in the datasheet for the 317 for an example of using
an NPN pass element. They use 3 195's in that diagram, but
you need only the single 3055.

It's an interesting idea to use PWM to control a voltage
regulator, but it's a completely different approach from what I
intended to build.

In reading your various posts it seems clear to me that you are
expending a lot of effort and have a lot of interest in this, which
is all to the good. But I also see that you are speeding by some
points where you could benefit by working to understand them,
rather than passing them by - which is what prompted me to reply.

Perhaps it will be worthwhile to refactor your
design and substitute a LM338, which has the requisite capacity.

No perhaps about it, it is definitely worthwhile. The earlier
part of my reply suggests how you can do it with parts on
hand, then later on add a pass element, or, as you mention,
substitute a 338.

For
now I think I will fool around with the existing arrangement.

Even at 3A output, the 3055 doesn't appear to be saturated as Vce is
only .9V. I picked up a couple of BC517 which have a beta of 30000
and 1A current capacity. Perhaps that will be more effective than the
BC557 in the pseudo-Sziklai arrangement.

Well, you may get it to work, but you won't learn why
it does, or why the previous attempts didn't. It is
my impression that you are leap frogging some of the
basics. Sometimes throwing bigger/better/stronger parts
at a problem is not in your best interests.

Ed