SoftStart®


SoftStart

The Astre Systems SoftStart®

Can be retrofitted on just about any transmitter,
any brand, any channel, UHF or VHF, klystron or not

 

Oscillograph of Ramp
With SoftStart®		 Oscillograph left is an MSDC klystron with SoftStart®.  Horizontal scale is 100 milliseconds per division.  Vertical scale is 50 amps per division.  Current after ramp is approximately 110 amps. Ramp time is approximately 1/2 second.

 

Oscillograph of Spike
Without SoftStart®		 Oscillograph left is a standard klystron using a relay-type step-start.  Peak current is 768 amps. Average current is 208 amps.  Horizontal scale is 25 milliseconds.  Vertical is 200 amps per division.

 

WRAZ Visual Beam Supply

Typical MSDC beam supply equipped with SoftStart®

SoftStart® technology, simply put, ramps the beam voltage on MSDC klystrons up from zero volts to full voltage of 25,000 VDC in a two-second linear time span. Since the input current to the beam supply is brought on line very gradually, there is no DC voltage overshoot or high inrush currents. The power company’s line “sees” a smooth ramp up to full-load current, not the momentary short circuit that occurs when primary power is turned on at full blast. Your peak demand is now your steady-state current demand. In other words, you do not exceed your normal operating current.

Shut down is very fast, too. Beam shutdown time is ½ cycle (8 milliseconds). With this very fast shutdown, chances of damage to expensive tubes and equipment are minimized.

On October 21, 1994 WFVT TV/55 in Charlotte, N.C. became the first station to utilize SoftStart® technology on a klystron transmitter.

WFVT operates at 240 kilowatts output, 24 hours a day with an Astre Systems MSDC transmitter utilizing SoftStart® technology on all six 60-kilowatt klystrons. The power bill for the month of January ‘95 was just a bit over $11,000 !

This system allows WFVT to turn all six power amplifiers (PA's) of their Astre Systems 240-kilowatt MSDC transmitter on line at one time, without dimming all the lights for miles around, or putting their “Peak Demand Factor” into orbit. In fact, they save a bundle on power bills.

SoftStart® is a registered trademark of Astre Systems Inc.
Copyright © 2002 by Astre Systems Inc. All rights reserved.    		 Home