[SBE] Phasor current draw

[Edwin Bukont]

Thank you Curt and others. 

Edwin Bukont CSRE, DRB, CBNT 
V- 240.417.2475; F- 240.368.1265 

 




 

> From: curt at spam-o-matic.net

> To: sbe at sbe.org

> Date: Tue, 14 Jul 2009 08:15:07 -0400

> Subject: Re: [SBE] Phasor current draw

> 

> On Monday 13 July 2009 04:06 pm, Edwin Bukont wrote:

> > 

> > I am trying to create a DA/NDA remote control for a 3-tower phasor system. 

> > The system has remote for choosing transmitters and Day or Nite. It does 

> > not have remote for choosing DA/NDA. 

> > 

> > 

> > 

> > Currently, someone has brought out the Tx and D/N to 240VAC relays with 30A 

> > contacts. Is this really necessary? 

> 

> If you're talking about the RF switch contacts, during switching it should

> be zero ! ( it does mute the TX during the switch, right ?? )

> I use 5 times the calculated RF current when buying contactors.

> 

> The solenoids that actually throw the contactor arms, the inrush

> current is theoretically infinite, but in practical terms I use 8 amps

> at 240 as a rule of thumb. ( 16 amps at 120 volts )

> The measured current is around 2 amps, ( at 240 ) but that's what a meter 

> will show. A scope will show considerably higher.

> It's a question of how much reliability/voltage drop/safety margin do you want ? 

> Once "settled" the solenoids will be around 1 amp, more than enough to

> burn them up in relatively short order.

> 

> The control relays, 24 volt coils are typical.

> 

> -- 

> Cowboy

> 

> http://cowboys.homeip.net

> 

> Just to remind everyone. Today, Sept 17, is Linux's 5th birthday. So

> happy birthday to all on the list. Thanks go out to Linus and all the

> other hard-working maintainers for 5 wonderful fast paced years!

> -- William E. Roadcap <roadcapw at cfw.com>

> 

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