Will,
To read pressure you measure the difference between the water levels in each
part of the tube when the blower is on. The part of the tube that is
connected to the amp will get pushed down and the other side of the "J" will
get pushed up. It is the difference between these two sides that is the
measurement.
With the blower off the water level in each part of the tube will be equal
height to the other.
What you are describing is only measuring one side of the tube. That will
only give you 1/2 the inches.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Will Matney
> Sent: Tuesday, May 23, 2006 11:07 PM
> To: amps@contesting.com
> Subject: Re: [Amps] Alpha 91b fan/blower motor
>
> Gary,
>
> The pressure on the outside is the low pressure and the pressure in the
> chassis is the high. With the blower off, that's the low pressure or room
> pressure where the water is settled. The difference between low and high
> shows the back pressure. The low side though, I don't understand what your
> saying? I always checked them the same as the set ups shown in the
> handbooks showing the same setup using the tubing. Are you counting the
> pressure above the chassis as the low pressure? It should be the same as
> the outside pressure unless the cabinet is not ventilated well enough. On
> most Alpha photos I've seen the tubes chimney runs right to the top and
> out the vents. You could check it that way but in reality it should be the
> same, especially if it set up that way. I doubt that perf metal will hold
> back the outgoing air flow very much. Now if above the chassis wasn't
> ventillated very good to the outside where it caused a restriction to
> flow, then yes, the above chassis would be used I
> would think.
>
> What most have been doing with the high speed blowers is cutting the speed
> back with a rheostat. Then if the temperature gets so hot, a thermostat
> shorts out the rheostat and full voltage is applied to the motor. In his
> case, my guess he has a fan already slow enough, and I'm afraid may be too
> slow.
>
> Best,
>
> Will
>
> *********** REPLY SEPARATOR ***********
>
> On 5/23/06 at 10:41 PM Gary Schafer wrote:
>
> >You want to read the difference in water level between the high and low
> >side
> >to obtain inches of pressure. Not the difference from no pressure to
> >pressure.
> >
> >Speed will have the greatest effect on pressure under load.
> >
> >73
> >Gary K4FMX
> >
> >> -----Original Message-----
> >> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On
> >> Behalf Of Will Matney
> >> Sent: Tuesday, May 23, 2006 10:11 PM
> >> To: amps@contesting.com
> >> Subject: Re: [Amps] Alpha 91b fan/blower motor
> >>
> >> Bob,
> >>
> >> Had they removed the label on the old motor where you couldn't see what
> >> the RPM and HP was? The RPM is what makes the flow or speed of the air
> >> throught the amp. The pressure is created by the size of the blower
> wheel
> >> which in turn sets the motors HP. The pressure is one of the most
> >> important things and that may be something you have to check. You can
> >> check this by using a clear rubber tube filled with some water. One end
> >of
> >> the tubing will be hooked to a fitting that goes into the chassis where
> >> the blower goes into. Let it loop down under the chassis so it will
> hold
> >> water in it. The other end is supported up higher where the whole thing
> >> will look like a big J so you see a water level in it. The high end is
> >> also left open. Turn the blower on and pressurize the chassis. The
> water
> >> will move up in the tubing. Make a mark at the water level both
> >> pressureized and unpressureized. Then measure the distance to see how
> may
> >> inches it moved. This will give the back pressure in inches rea
> >> ding, and can be used to check against the tables in the tube specs as
> >to
> >> be the right amount or not. If it's correct (matches), you'll have the
> >> correct pressure and flow. I think there's some charts in the ARRL
> >> Handbooks too. If you have to drill a whole to do the test, simply plug
> >it
> >> up when your done.
> >>
> >> Best,
> >>
> >> Will
> >>
> >> *********** REPLY SEPARATOR ***********
> >>
> >> On 5/23/06 at 9:47 PM KR4DA wrote:
> >>
> >> >I recieved the fan today.
> >> >BUT the SPECS on the label say RPM 1100 and HP 1/500
> >> >
> >> >The web page says RPM 3000 and HP 1/200
> >> >
> >> >I hooked the fan to the NEW motor and WOW I don't think 3000 RPM
> >> >would be GOOD.
> >> >The fan spinning on the NEW motor does put out a nice flow of air.
> >> >At 3000 RPM it would really be spinning.. my gut feeling is that 3000
> >rpm
> >> >is to fast.
> >> >
> >> >
> >> >Geees I wish I could get an answear on WHAT THE RPM SPEED IS IN THE
> 91B.
> >> >I AM CONFUSED NOW AND IT PROBABLY ISN'T 3000 RPM AS WAS I
> >> >WAS LED to believe and TOLD to me by ALPHA.
> >> >Who the heck knows about these amps???????????????????????????
> >> >or should I say really knows about blower motors and needs for
> cooling.
> >> >
> >> >I also posted this to the ALPHA GROUP 2 weeks ago on YAHOO ...
> LOL...no
> >> >responce.
> >> >
> >> >
> >> >
> >> >KR4DA wrote:
> >> >
> >> >>
> >> >>The motor currently in MY 91B is labeled as:
> >> >>BOMAX type b-jc 50/60hz .64amp 301-6623.
> >> >>Bomax seems to be out of business.
> >> >>But web page is up but no refernce to this number.
> >> >>
> >> >>Anyone have suggestion for replacement???
> >> >>
> >> >>
> >> >>I do not know how critical it is but there are on the web at
> >emotorstore
> >> >>c frame open motors CLOSE to the same specs.
> >> >>
> >> >>Plate thickness 16.6cm
> >> >>shaft deminison .186 x 2in
> >> >>115v .64a CW rpm 3000
> >>
> >>http://www.emotorstore.com/productdetail.asp_Q_catID_E_6_A_subCatID_E_
> >> >>251_A_productID_E_402_A_skuID_E_25484
> >> >>has this part do you think I would it be ok to USE IT???
> >> >>
> >> >>I don't blame anyone but really think a person derserves better
> >> >>communication from ALPHA on getting this fan.
> >> >>This AMP cost me $2,748 in April 1997 that was alot of money to me.
> >> >>And now cannot use it for HOW LONG???? until I get a motor.
> >> >>
> >> >>Frustrated Bob KR4DA
> >> >>
> >> >>
> >> >>
> >> >
> >> >--
> >> >Bob
> >> >Vmoa chat list -> http://autos.groups.yahoo.com/group/vmoachat/
> >> >Vmoa tech list home -> http://autos.groups.yahoo.com/group/vmoatech/
> >> >
> >> >
> >> >Middleburg Fl (South Jacksonville)
> >> >ICQ 13912841
> >> >Web Page http://bellsouthpwp.net/k/r/kr4da
> >> >
> >> >Visit the FDXPG at http://www.geocities.com/w4wx1/
> >> >
> >> >Ham Radio Calls: KR4DA FG/KR4DA J79DA HK0/KR4DA
> >> >
> >> >Motorcycles CBMMA #4
> >> >1977 XS750D 1J7008405
> >> >1997 Vmax12J VMOA #504
> >> >
> >> >
> >> >
> >> >_______________________________________________
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> >> >Amps@contesting.com
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> >>
> >>
> >>
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> >
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>
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