A minor formula exists in the P=EI formula in the original message. The corrected version is below. To many annoying phone calls! Sorry about that! Dave ----- Original Message ----- From: "DaveH" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Sunday, January 14, 2007 6:27 PM Subject: Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc.
> Erick, > I agree with you! The only difference will be any increased > efficiencies in the switcher over the mag and that will be small. I have > had > a Master Electrical License for 38 years. A physical law of science says > that 746 watts equal 1 horsepower> There is no deviation from that > scientific fact. In addition, if the equipment that is powered by the > astron, draws 30 amps, it's going to draw 30 amps on the switcher. THAT > CANNOT CHANGE> The power supply, both switcher and mag type, will draw > the > required line current that is demanded by that load. Ohm's law says P=EI > (power ((wattage)) = E((voltage)) multiplied by the amperage ((I)). If 30 > amps > are required at 13.8 volts the resultant power consumed will REMAIN THE > SAME POWERED BY THE MAG OR SWITCHER SUPPLY. Since this physical law cannot > change, then the efficiency differences between the two types of supply > will > be the ONLY POSSIBLE DECREASE IN CONSUMED ELECTRICITY. > Since efficiency is the ONLY POSSIBLE GAIN and the switcher cannot > generate electricity and there is no perpetual motion, needed magnetizing > current decrease and possible utility current power factor improvements > are > the ONLY POSSIBLE IMPROVEMENTS THAT CAN OCCUR. If you consider these > facts, > you will instantly see that utility cost reductions will be minimal at > best. > Electrical company power charges are calculated in KWH (kilowatt hours). > That is calculated by the formula KHW (killer what hours ((hi hi)) = > wattage load (both apparent and actual) multiplied by the time used and > divided by one thousand. Since the inefficiencies are these SMALL > differences, any real electrical cost savings will be in pennies on the > monthly bill and that is if the utility apparent wattage is in line with > actual use (power factor corrected). > As you can see, the only real advantage to the switching supplies are > mostly physical. By the way. Accurately measuring these electrical > differences with metering equipment can get quite complicated since ac > power factor is involved. To correctly measure this you need to correct > power factor by using correction capacitors. That is why utility meters > have > a designed and approved accuracy of 1.5 to 2 percent (this is national > standard and regulation required). If anyone believes they are going to > save > any substantial amount of money by converting to switchers, they are going > to be rudely awakened. It would take decades to recoup the cost of such > equipment replacements based upon utility savings. > One last myth left to clear up. A power supply connected to ac current > and left turned on 24/7/365 is the way to insure increased equipment > longevity. I have heard many people say they must "turn their power supply > off when equipment is not being used to save electricity." NOTHING COULD > BE > MORE ERRONEOUS. The ONLY electricity being consumed when the load is > switched off, is magnetizing current and voltage correction current from > leakage etc. > Since this is relatively minute, those "significant savings" are > nonexistent. Once again we speak of pennies. If you consider the stress > caused by switching the power supply on and off many times, in the end you > loose. Life expectancy is decreased by in rush, each time the unit is > re-energized. I have had Astron mag. supplies functioning for DECADES with > no failure. As long as the input is protected by GOOD electronic spike > suppression, failure is mostly limited to age or abuse (possible load > shorts). > I can only hope this helps clear up confusion and to eliminate > conjecture regarding these subjects. > > David R. Henry LME > > ----- Original Message ----- > From: "Eric Lemmon" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Sunday, January 14, 2007 3:07 PM > Subject: RE: [Repeater-Builder] Re: Switching Power Supply vs. Astron Etc. > > >> Larry, >> >> You have a golden opportunity to provide an extremely valuable service to >> the radio community! If you can obtain the use of a wattmeter, you can >> make >> a comparison between the two power supplies. One such meter is the "KILL >> A >> WATT" meter that is sold under several brand names. It is inexpensive, >> and >> accurate enough for our purposes. >> >> Try measuring the power- both real and apparent- drawn by the same >> equipment >> while operating on the TPN1110B supply, and again while operating on the >> TPN1151A supply. Make a note of all parameters in both the idle state >> and >> while transmitting. I'll be surprised if the energy used by the switcher >> is >> not much less than the ferro-resonant unit. >> >> Keep in mind that the utility charges its customers for the consumption >> of >> real power in watts over time, in kWh. In an AC circuit, the independent >> measurement of volts and amperes does not equal watts unless the load is >> resistive, which is definitely not the case with a power supply. >> Therefore, >> the measurement of current drawn by each power supply is meaningless, >> since >> it is not in phase with the voltage. The product of unsynchronized >> measurements of volts and amps in an AC circuit is VA, not watts, and >> will >> differ from watts depending upon the power factor. But, I digress... >> >> Just the watts consumed by each power supply in standby and transmit >> modes >> will be important to know. Once you see the difference, you may be >> inclined >> to stick with the switch-mode power supply- especially if you are paying >> for >> power. >> >> 73, Eric Lemmon WB6FLY >> >> >> -----Original Message----- >> From: [email protected] >> [mailto:[EMAIL PROTECTED] On Behalf Of >> [EMAIL PROTECTED] >> Sent: Sunday, January 14, 2007 11:28 AM >> To: [email protected] >> Subject: Re: [Repeater-Builder] Re: Switching Power Supply vs. Astron >> Etc. >> >> Would I gain any advantage by changing out my Motorola MICOR Repeater >> TPN1110B supplies (the ones with the constant-voltage transformer) to the >> TPN1151A Switching power supply? I have a few spares of each type, but >> most >> of my MICOR Repeaters came with the 1110B supply installed. >> >> I don't know why there were two types of supplies offered with the MICOR >> Repeater/Base Station radios. The switching supplies seem to be very >> quiet >> (even around an HF radio), as far as I have been able to determine. Some >> of >> the MICOR service manuals have sections for both supplies, to cover the >> particular unit that was supplied with the user's station. >> >> LJ >> >> >> >> >> >> >> >> Yahoo! Groups Links >> >> >> >> > > > > > > > > Yahoo! Groups Links > > > >
