-----Original Message-----
From: Brandon, Reid [mailto:Reid.Brandon@cpii.com]
Sent: Wednesday, February 18, 2004 11:44 AM
To: Mandel, Harold
Subject: RE: Tech Question 3CX1500A7 vs. 3CPX1500A7
I recommend using a heater voltage of 4.9 V, regardless of which triode
you employ (3CX1500A7 or 3CPX1500A7)
The 3CPX version is designed to be used as a pulsed amplifier in MRI,
scientific, and laser excitation applications. As an rf amplifier at
power up to 2500 Watts it is not necessary to raise the heater voltage
with this tube.
Running slightly under voltage will help increase tube cathode life. A
5% reduction is allowable for this tube provided it isn't being pulsed
to power levels above 2500 W.
The only difference in the two products is that the CPX version has a
longer ceramic envelope, allowing it to be processed to higher plate
voltage without external flashover. The cathode is identical in both
tubes, but we allow raising the heater voltage in one case for higher
peak power. The warranty is lower in total hours for the CPX version,
this fact may be a consideration you haven't addressed.
I recommend the 3CX1500A7 for "normal" (non-pulsed) applications.
Best Regards,
Reid Brandon
Applications Engineer
CPI Eimac division
_____
From: Mandel, Harold [mailto:hmandel@bechtel.com]
Sent: Wednesday, February 18, 2004 3:11 AM
To: 'powergrid@eimac.cpii.com'
Subject: Tech Question
Importance: High
Dear Friends,
In an ongoing project the power triode type 3CPX15ØØA7 was discovered
to possibly provide increased performance and a better MTBF.
The project transmitter will use a 3.ØKV, 3.Ø Ampere anode supply
and will operate from 1 to 3Ø MHz. , with 1/1Ø PPS service at 15MHz.
The plate transformer and the filament transformer are separate
components.
The P.W. Dahl filament transformer, when delivered, was found to be
5.Ø v.a.c., R.M.S., (nominal), at 2Ø amperes (calculated). The
transformer is
of the hypersil variety, slightly over-voltage under no-load,and capable
of more than 2Ø amperes before reaching saturation.
Is it possible to purchase 3CPX15ØØA7 triodes to use in this application
and not void the warranty because of insufficient filament voltage or
prematurely deteriorate the tube elements as mentioned in the tube
application guide ?
If the plan is not operating the tubes past a nominal 2.8KW, two-tone
ICAS, A3j or P5j (intermittent), would great harm still be done?
Thank you.
Sincerely,
Hal Mandel
<< hmandel@bechtel.com <mailto:hmandel@bechtel.com> >>
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