[Amps] Benefits of 3-phase power?

[Karl-Arne Markström]

Gentlemen,

I can second your observation that 3-phase power feed is superior to single-phase.

When power levels much more than 1 kVA input are used,
it is possible to observe poor AC regulation with keying even on European standard 230V outlets.

If constant power regulated switch-mode power supplies, such as in the Collins HF-8023/32, are used, 
the lowered input voltage will be compensated by a higher line current, making the situation worse.

There is a marked difference in AC line regulation when comparing transmitters with the same output power
using 3-phase and 1-phase connections. My own Standard Radio SSA1000 1 kW+ transmitter for example, 
using a 3-phase 230/400 V AC feed, does not blink any lights in the house 
even when transmitting full power into a mismatch. 

It appears that the standard European practice to provide 3-phase 230/400 V power, 
usually fused at 20A or 25A per phase,even to small dwellings 
is a blessing for the QRO enthusiast.

73/

Karl-Arne
SM0AOM

----- Original Message ----- 
From: <ka1xo at juno.com>
To: <genewill at ordata.com>
Cc: <amps at contesting.com>
Sent: Sunday, November 16, 2003 8:22 AM
Subject: Re: [Amps] Benefits of 3-phase power?


> 
> Dear Gene,
> Having been fortunate to have 3-phase power available in the lab where we Type-Accepted DC Powerplants for cellular transmit sites I took advantage of the situation and hooked up a strip chart recorder to the three hot legs of the 5-wire service and to the three wire service of the split single phase mains supply to be able to tell the customer about sags and surges. While both services suffered equal amounts of transient pulses, measurable from 3 nS up to 1mS, and in equal amplitude, the three-phase service suffered less than one-third the amount of events from 1mS to 1S. The customer decided to bring in 3-phase power to as many sites as were possible, the big hurdle being the nearby availability of three-phase lines in the street.
> 
> The everyday advantage to using 3-phase mains is smaller wire diameter and lighter motor frames for the same HP. 
> 
> But who has 3-phase going to their house?
> 
> Hal
> KA1XO
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