On Feb 8, 4:40*pm, wrote:
Thanks for that Lamont.
The device is a transceiver and the power usage on:
Transmit is 850VA and on
Receive is 210VA

The result you and my other friend get (which is the same) seems
enormous.

John Plimmer, Montagu, Western Cape Province, South Africa
South 33 d 47 m 32 s, East 20 d 07 m 32 s
RX Icom IC-756 PRO III with MW mods
Drake SW8 & ERGO software
Sony 7600D, GE SRIII, Redsun RP2100
BW XCR 30, Sangean 803A.
Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270
Kiwa MW Loop, PAORDT Roelof mini-whiphttp://www.dxing.info/about/dxers/plimmer.dx

On Feb 9, 12:17*am, "The Shadow" wrote:



wrote in message

...

I would be grateful for the advice of one of our technically minded
members:
The new radio I have coming merely states it's power consumption as
210VA, as it is a multivoltage radio.

What consumption in watts/amps does this translate to at 240 volts AC
mains?
Also. if I used an inverter to drive it off a 12 volt DC battery, what
would the power consumption in amps then be?

POWER CONSUMPTION IS IN WATTS NOT AMPS

A friend who helped me wrote:
Watts = Volts * Amperes so 210VA = 210 Watts

NOT TRUE - WATTS = V*A*COSINE OF THE PHASE ANGLE

210 Watts means 210 / 240 Amps which is .875 Amps.

If you want to use a 12V battery, 210 Watts means 210 / 12 Amps or
17.5 Amps. This assumes the AC supply is as efficient as the DC
supply. It won't actually be quite as efficient, so you're likely to
need fewer Amps, maybe 14 or 15 but that's a guess. Maybe you can ask
as the DC current depends on their design which is not known to us
yet.

Those numbers look very high to me. I suspect they've made a little
mistake.

I replied:
it does seem very high to me for 210VA. at 240 volts AC mains.
As just a poor guess I would estimate
0.5 amps at 240 volts AC mains
and 8 amps at 12v DC
but I cannot calculate it.
_______________________________

So what do the experts out there think?

Would be grateful for your help.

WHAT KIND OF RADIO IS IT -- 210 VA IS TOO HIGH FOR A RECEIVER -- MORE LIKE A
TRANSCEIVER

Volt-Amperes VA usually refers to AC apparent power - it takes into account
reacive components see URL:http://www.allaboutcircuits.com/vol_2/chpt_11/2.html

True power in an AC circuit is IxE if there are no reactive components
otherwise it is I squared R or ExI x Cos theta

So True Power (Watts) does not equal VA unless the circuit is purely
resistive.

Assuming your device is resisive (or near to it) then see URL:http://www..sengpielaudio.com/calculator-ohm.htm

which indeed gives 0.875 Amperes

Again usinghttp://www.sengpielaudio.com/calculator-ohm.htm

which indeed gives 17.5 Amperes

Allowing for efficiencies and loss etc I would allow for 20 to 25 amperes
Most inverters will specify a power rating

Lamont- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

JP,

Message - "New Radio in South Africa"
http://groups.google.com/group/rec.r...866d6ff18a951c
I am getting another RX, an Icom IC-7700 see brochure at:
http://www.ab4oj.com/icom/ic7700/IC-7700_pre.pdf
ICOM IC-7700 - http://www.rigpix.com/icom/ic7700.htm
Minute-Video - http://www.youtube.com/watch?v=eJS0z-Y5hKc

You are talking about your new Icom IC-7700 Transceiver.
IC7700 - http://www.ab4oj.com/icom/ic7700/main.html
Icom IC-7700 Transceiver - Rated Power Consumption :
Tx Max. power 800 VA {Transmit 'Power Output' Mode}
Rx Stand-by 200 VA (typ.) {Receive Only Listening Mode}
Max. Audio 210 VA (typ.) {Receive Only Maximum Audio Output}

12 VOLT DC POWER SOURCE / SUPPLY
- = FOR RECEIVE ONLY USE = -
[NO MIC CONNECTED / NO TRANSMITTING]

240 Volts divide by 12 Volts = 20 f#

0.875 Amperes @ 240 Volts

0.875 Amperes times 20 f# = 17.5 Amperes @ 12 Volts

Add a 15% Power Supply Safety Factor :
17.5 Amperes times 15% (0.15) = 2.63 Amperes
17.5 Amperes plus 2.63 Amperes = 20.13 Amperes

Requires as a Minimum a 12 Volt DC Power Supply that
is Rated at 20+ Amperes. {25 Amps would be better.}

FWIW - Going from 240 VAC to 120 VAC the 0.875 Amperes
would become 1.75 Amperes {2 Amps}

Again these Rough Numbers are for "Receive Only" Use
-NOT- Transmit. ~RHF