[SBE] Phasor current draw

[Cowboy]

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

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