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[WA4JQS]

bryan
i was going to use the 220 type plugs also but had a dozen of the red ones left from a xray room install i did for G.E. and thought they would make the kids think before they tried to plug anything in the outlets.. btw they were 6's . just added a little color hihi..
73 Tony

[WA7PRC]

bryan
i was going to use the 220 type plugs also but had a dozen of the red ones left from a xray room install i did for G.E. and thought they would make the kids think before they tried to plug anything in the outlets.. btw they were 6's . just added a little color hihi..
73 Tony

Yes, Tony. Except for the extra cost, that doesn't hurt. "220 type" includes NEMA 6 and others. From the link I provided:

Further requirements might include specific coloring/marking such as for medical usage. If I ever get around to it, I intend to change from NEMA 6-20 to L14-20 for my amplifier feed. Why? Because I want to. 

Bryan WA7PRC

[KM4AH]

If they are red and have a green dot they are hospital grade. Anything with a green dot is hospital grade, but it is unlikely that if they are red they are anything else. There are at least four grades of receptacles, and the hospital grade is highest quality. So, that's good. My amplifier outlets are all twist lock, although I don't know that there is any particular reason for it other than that I was the Arrow Hart rep and got them for free.

[N8FVJ]

Mouser & DigiKey sells 16 amp at 10 ohms thermistors. Use two, one in each line for 240 volt input amplifiers up to legal limit. Amps like a 600 watt output can use one thermistor on a 120 volt AC line.

[WA4JQS]

i was a field eng for G E Medical Div for 10 years and yes they are red hospital grade units for use in OR and XRAY rooms. Have a few left still.. i plan of installing two series GE CL-200's in series in each leg of the 220 line for each amp.. i have some 4 lug terminal strips left over also guess the eazy way would be to mount one of them in each amp and use the thermistor between the new one and the old one.
73 Tony WA4JQS

[KM3F]

Here is my setup and has been in use for almost 8 years.
1. A dedicated 240 line to the shack area from the power panel with a 20 amp breaker feeding #12/3 WG.
2. In shack a heavy cord and plug into the wall outlet feeds a switch panel that has a DPST regular AC switch just like a SPST but DP.
3. One outlet for the amplifier across the 240 line.
4. More outlets from each side to common for 120 feeds to radio equipment.
One switch controls the whole station if needed.
This feed for station and amplifier are more than enough on one 20 amp circuit at any given moment  and show no visible signs of voltage drop to any of the equipment with the amplifier in use.
No lights, no pilot light dimming or flickering on any equipment.
In a blink of an eye the switch can be turned off, everything unplugged and removed as if nothing was ever there.
It's all legal and safe built out of electrical boxes and hardware all nippled together and wired with #12 and metal cover plates.
I also have a Variac to run the amplifier on and monitor the 240 line full time to see the commercial  voltage supplied to the house and keep the amplifier up to operating level during  the summer cooling and winter heating seasons when the commercial AC  sags a bit.
Sure beats trying to run off extension cords and over loading 15 amp 120v wall circuits..
Good luck.

[KM3F]

On my Ameritron 80B I lengthened the inrush time just enough to hear the relay pull up just because I want it that way.
I have a 6m amplifier that had no in rush ckt.
Having rebuilt the power supply filtering with more filter capacitance, I built and installed a in rush circuit with similar timing and can see the plate voltage come up in two steps from 1700  to 2500 vdc for a 4cx400 .
Works pretty nice.
Even my radio switching power supply has inrush protection from the factory.
Good luck.

[WA4JQS]

km3f:

what did you use in your in rush ckt

73 Tony

[KM1H]

Tony when I worked you from VP8SSI on 160 in 92 (do you still remember that QSO and comment you made at Dayton?) all I had was a 25' 240V run of 12-3 to the attic as the basement shack hadnt been finished yet; the regulation was pretty poor.

Later I ran 6-3 diagonally across to the opposite basement corner to a box and then fed individual 10-3's to 3 operating positions and to the amp repair bench....no more regulation problems.

At the main panel I have a pair of Littlefuse V251BA60 Varisistors at the main breaker, they are 50 kA, 880 joules, plus .01 uF which is good for some poise bypassing. They have survived lightning hits on the utility lines for the past 24 years and the only equipment failures were attached to telephone lines....a couple of Faxes and modems.

Carl

[W4HCB]

Has anyone tried the Ametherm circuit protection thermistor? They will send you samples free by UPS just for the asking. They sound like they would work and only one part to put in.

Hugh W4HCB

[WA4JQS]

Carl Wow man that does bring back memories.. yes i do. hi hi.. i had a lot of fun on Thule Island in 92 and Peter 1st in 94..BTW The alpha 89 that i sent to Glenn for repair last month was the beta unit we took to Peter 1st. the one that had the snow piled up on it in the Alpha AD in QST. hihi.. just goes to remind us of how small the world really is because of ham radio.
73 Tony WA4JQS / VP8BZL.
btw still have the logs from both in the shack.

[KM1H]

Every time someone says you cant work DX on 160 with a low dipole that QSO comes to mind. With an inverted V apex at 55' and the ends at 3' and "only" 1200W I thought that I would be in that monster pileup for many hours. Then after one call you came back!
At Dayton you said I was about 10 dB above the bedlam and the only call you could copy. Over the years after that 160M propagation gurus have accepted that NVIS straight up into a duct does indeed happen. I put that antenna and tower up and the rig in the attic with one purpose....work you on 160 and 10 where a HB 4 el sat just above the top of the temporary tower which is still there.....no concrete just a base plate on the dirt and guyed to trees.

Carl

[KM3F]

What did I use in my in rush circuit?
A DC relay  with contacts capable of handling the through current with some to spare.
The winding can be any  low DC voltage value.
The circuit will have a rectifier diode, a dropping resistor to put the relay winding within it's rating voltage range. Use Ohms law to calculate.
A Electrolytic capacitor just above the relay winding's operating voltage at the capacity value you need like 50 mf etc..
Arrange the circuit to power up at main switch on.
The relay circuit is built with a delay time constant you want by adjusting either or both the capacitor and series charging resistor for the  delay  you want.
The capacitor goes across the relay  winding to initially shunt it out until the cap voltage rises far enough for relay operation. Time constant.
A 25 ohm 25 watts or higher resistor  across the open relay contacts to absorb the initial inrush current before the relay timing circuit charges enough to operate the relay.
When the relay operates and closes the contacts, the resistor is shorted out and you have full ac power to the amplifier.
As soon as the power is switched off the relay winding discharges the capacitor and it will do the inrush control all over again.
Build it on a small board and find a location to mount it.
Wire with proper  wire size.
Good luck.

[WA7PRC]

What did I use in my in rush circuit?
A DC relay  with contacts capable of handling the through current with some to spare.
[snip]

The step-start circuit I use in my SB-220:

(click for large image)
All RED circuitry is added.

I had a 3PDT/10A relay w/ 24VDC coil in my junque box. D1 rectifies 120VAC (170V_PK). R1 drops it to 24V. R1 x C1 takes a second or so to charge to 24V. K1 contacts short across R2 & R3 (chassis-mounted wirewound resistors).

[KM1H]

I have three amps  2kd5, l4b and tl-922a. that I want to add in rush protection too. just wonder if the one dx eng.  sells by ameritron is worth the money or should I go ahead and get the kits from Ohio and install. was thing the ready made would save me a lot of down time. 
thank

I forgot to mention that the 240V Ameritron unit has a history of frying itself, dont know if it has been corrected.

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=arb%20704%20problems

The L4B and TL-922 have wimpy transformers that limit the inrush. I have a LK-500ZC with the big external Dahl "Power Pack" and havent had a single inrush problem since I bought it new in 1986. An Alpha 76PA (3 tubes) on the second station was used as a Carribean contest amp for decades without inrush problems; users who forgot to change antennas and/or ran excessive grid current did all the damage to the poor little 8874's.

Other amps here as backups or as AM/SSB linears with vintage tube gear are Clipperton L, MLA-2500, DTR-2000L, Hunter 2000C and several NCL-2000's just keep working fine.

A problem may be when some replace the original filter caps with ridiculously high values that take out power switches.

Carl