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Ameritron AL-811HXCE - Correct 240V AC Wiring?

Discussion in 'Amateur Radio Amplifiers' started by MM0IMC, Oct 1, 2012.

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  1. MM0IMC

    MM0IMC Ham Member QRZ Page

    Hi folks,

    I recently bought a brand new Ameritron AL-811HXCE and have a question about the wiring connections for the transformer.

    The wiring for the mains power seems a little odd to me for something that supposed to be wired for 240V AC as standard (811HXCE), A to 1 and B to 2 which is normal, yet D to E is still linked. The HV meter shows a voltage of just below 1800V DC, my mains (line) voltage is 240V AC +/- 5V.

    Should I cut the link between D and E?


    Ian - MM0IMC.
  2. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    No, why would you want to do that?

    Just under 1800V is really pushing the heck out of 811As.:p

    The tube's inventor, RCA, rated them 1500V max for ICAS service.
  3. VK4TUX

    VK4TUX Ham Member QRZ Page

    It would appear from the schematic instruction to drop secondary V as D-E opened is rated for higher primary V;

  4. VK4TUX

    VK4TUX Ham Member QRZ Page

    The AL-811H is supplied with a NEMA 5-15P plug for 120Voperation. The power required to operate the AL-811H/HY isnot high enough to warrant 240V operation unless 120V is notavailable. The fuses should be 12 ampere fuses for 120V andthey must be changed to 8 amperes for 240V operation. Thediagram to the right shows the proper wiring for 120Voperation.Operation on a voltage of 240V is not required, nor will it​
    necessarily improve performance. The power transformer will

    perform equally well with a power line frequency of 50 Hz or 60Hz. The Transformer Connections chart at the bottom of thispage shows proper connections for various line voltages.​
    WARNING: The green wire connects to the chassis of theamplifier and it must connect to the safetyground of the outlet.​
    The AL-811HX (export model) is wired for 240V, 50/60 Hzoperation. The appropriate plug is not provided for this model.You must wire the proper plug on the end of the power cordsupplied. Simply cut the existing plug off and wire theappropriate plug in its place. If the line voltage in your countryis not 240V, then you must change the transformer to theappropriate setting indicated by the chart below. ​
    Note: the AL-811HXCE transformer allows operation on 100V line voltage incountries such as Japan.
    The wiring between the fuse box and the amplifier AC outletmust be 14 gauge or larger in order to supply the operatingcurrent required (10 amperes) without a significant drop in the​
    line voltage. The outlet should be fused for the wire gauge used.
  5. MM0IMC

    MM0IMC Ham Member QRZ Page

    I'd rather run it at the rated voltage, not what it's running at the moment. It came out of the box like that...
  6. W9GB

    W9GB Ham Member QRZ Page

    CORRECT. This HF amplifier shipped outside of North America (Export) is wired for a 240 VAC input.

    The AC power transformer in a majority of these 120/240 VAC HF amplifiers use DUAL 120 VAC primary windings.
    For 120 VAC usage in North America (and Japan), they are wired in Parallel.
    For 240 VAC usage in Rest of World, they are wired in Series (linking of D and E).

    The A, B and 1, 2 connections are related a Buck Boost winding for correct matching
    to the various global voltages of: 220, 230, or 240 VAC.
    You need to determine your local voltage in North Ayrshire.

    For United Kingdom, Voltage tolerance of 230 V +10%/−6% (216.2 V to 253 V),
    widened to 230 V ±10% (207 V to 253 V) in 2008.

    The UK system supply voltage remains centered on 240 V.
    Formerly 240 V in mainland Britain and 220 V in Northern Ireland.

    For the AC plug in UK, you are likely using BS1363, also referred to as the 13 Amp plug.

    In the UK since 2004, AC wiring color usage is changing.
    This is being done for harmonization with EU countries standardization begun in 1990s
    and overall reduction in multiple global AC wiring standards.
    Last edited: Oct 2, 2012
  7. N2EY

    N2EY Ham Member QRZ Page


    For all 220/230/240 volt operation, D to E is linked, C to D is open and E to F is open.

    If D to E is not linked you'll get nothing at all.

    If C to D or E to F is not open you'll blow a fuse or worse.

    All adjustments are by the A, B, 1 & 2 connections. Connecting for a higher mains voltage gives a lower B+.

    You are probably OK as-is.

    73 de Jim, N2EY
  8. MM0IMC

    MM0IMC Ham Member QRZ Page

    Thanks for the input.;)
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