[SBE] Phasor current draw

[Cris Alexander]

Edwin:
 
If those are the solenoid-type RF contactors, at 250 volts you can expect
about 6-7A current draw per switch nominal, but the inrush current may be
considerably more. So with five towers, it seems that a 30A relay would be
boderline. 
 
You should be able to jeep some 24V relays in there to control the phasor
remotely. Just hang the NO contacts of a 24V-coil relay across the actuator
lines for each mode.
 
______________________________
Cris Alexander, CPBE, AMD, DRB
Crawford Broadcasting Company
Denver, Colorado
(303) 433-0104
(303) 433-0905 Fax
Assoc. Member AFCCE

  _____  

From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Edwin
Bukont
Sent: Monday, July 13, 2009 2:06 PM
To: sbe
Subject: [SBE] Phasor current draw


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?
 
The mode change itself appears to throw maybe 5 contactors including the
towers.  I realize that in the DA mode it has to support the current
involved with switching of Day and Night.
 
I want to do my additional control with a 24VDC coil and contacts rated at
15A/250VAC.
 
Am I missing something here.  Do I really need those big power relays or
will something smaller suffice.  I do not know what the current draw is,,and
it would be difficult to amp clamp.
 
Anybody have any ideas what a 30-40 year old three tower, 3 modes Phasor
array might draw in Amps at 250VAC during switching?
 
Thanks

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

 



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