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G8MNY  > TECH     25.02.10 00:44l 107 Lines 5851 Bytes #999 (0) @ WW
BID : 49774_GB7CIP
Read: GUEST
Subj: SIP2300 Generator info
Path: IZ3LSV<IK2XDE<DB0RES<WA7V<N9ZZK<N4JOA<GB7CIP
Sent: 100224/2221Z @:GB7CIP.#32.GBR.EU #:49774 [Caterham] $:49774_GB7CIP
From: G8MNY@GB7CIP.#32.GBR.EU
To  : TECH@WW

By G8MNY                                       (Updated Aug 08)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

I bought a MEDUSA SIP2300 4 stroke petrol generators as the were so cheap (just
in case we have power cuts!). It is the same generator as the WOLF 2.3kW.

It is fairly quiet @ 73dBA @ 4m. The large 12 l tank gives approx 10 hours run
time. It is not too heavy @ 83kg full, 41kg dry, to move it by oneself (only on
& off a low level trolley & lift into van etc!).

                                        Gauge   Filler
                   _.==.._   Tube
/~~~~~~Tank~~~~~~~\               /"     Large 12L Tank    "\ Cage
-------------------      Fuel Tap ===========================
\_____________/~~~~      & filter\|"""""~~~~~~~~~~~~~~~"""""|
    Tap(0)   elec            STOP [] OK  on  " AC "      AC
Choke //   Sol\____         SWITCH |_  Oil   = =  = = _|  2x13A
Ŀ  /~~~~~\\.  Pull           ۳~~""---..........---""~~
۳In- ,' /~~~\//\\ Start          ۳F ENGINE      |     |  
۳Take  ( )                   ۳A        (=)oil ALT |  
 \ \___/  /                 ۳N   ________|_____|  
     ' Ŀ `                           
"""""""""""""""""""                

I have modified it for /P contesting, to power several 400W valve PAs for as
per my bul on "Petrol Gennys for /P SSB". With my rev up modification (add a
solenoid for FEED FORWARD compensation) the measured performance is now...

Generator      Unmodified                   Modified   
 Load kW        Volts  Hz               Volts  Hz  Uplift %
   0             250   55                250   55    0
  0.1            235   54                238   55    0.3
  1.0            225   53                234   55    4
  2.0 Rated      215   51                235   55    6.4
  2.3 Old Peak   200   49                233   55   16.5
  2.5            190   47                235   55   23.7
  3.0 New peak   180   45 33% throttle   220   54   22.2  @ FULL THROTTLE!

It is not intended that continious loads over 2kW be used, just speech peaks
etc. to go to 3kW peak load. Before the modification it was not possible to
activate the 10A thermal output trip on good power factor loads, after this mod
it is now possable!

At 50Hz you only get 225V output, but it is more economical to use lower RPM if
the peak power is not needed! There is no 2 speed option for this, but a long
screwdriver will adjust it OK. Note the off load voltage is quite a bit higher
than even with a 100W lamp.

Other Mods I did were..
1/ Added earth bonding from engine, to frame, & to the electric panel plate.
2/ Added earth lead & earth clip for external earth stake.
3/ Added engine ignition lead screening, & made a screen tube for the plug cap.
4/ Painted Alternator casing black to imporve heat dissapation.

CIRCUIT
I have reverse engineered the diagram...
                                                                    STOP
 o/oĿ
 gn/ye         2x13A  Ŀfront      External Earth                
             E   AC    E    __panel                                   
       bk  N   L     N   L  ///                                        
        Ĵ   )       - - - - - - - - - - - - - -         
          )Ĵ          |  ´<       
       Run                    | __D2                 D1  |         
       Neon   10A              | /_\ __              __    |  bk/    
            Trip    bk        |    \_/Q2          Q1\_/    |   wh    
        Ĵ               |     \     ZD  ____/     |         
               rd     Added   |      47Ĵ<Ĵ         
   25u 450V         Solenoid  |              200     |       Oil 
   ĴĿ(155V)     -------  | 50   Ŀ +C1   |      Neon 
                   =====   |       __ 1k C2  ===47u |          
                  _(((()_  |     D3/_\  === 2k  63v  | ye       
   ye  ye           0.2    |  )  
                            |        P C B               |           
 _ _ _ _ _ _  _ _  _ _ _ _ _|_ _ _ _ _ _ _ _ _ _  _ _ _ _| _ _ _ _ _ 
   or  or    rd   bk  |          __  oil       bk              bk/wh 
   1.4      1.8     | Timing |(  o/o         5kĿ   
__ ((() ==== (((()    | Pickup |(  Ĵ               Spark  ||(6k 
///  ==== (((() ====     |  -2V   __  1n ?                 Plug   ||(___
          Ĵ>          |        ///                              ||( 1
     A L T E R N A T O R   |   C R A N K C A S E        M A G N E T O __
                           |                Ŀ               ///
                                       TUBE__ gn/ye __ FAN
                                      FRAME///       /// COWLING

ELECTRONIC IGNITION
The electronic ignition works in a strange way, as top dead centre approaches a
voltage of -80V or so is made by the magneto primary, this is shorted out when
the timing pulse triggers the SCR, shorting this voltage & producing an
ignition voltage in the magneto secondary.

Only one wire from the crankcase handles both the timing & the oil status. If
low oil, the crankcase oil switch is not made, & the ignition is killed after
the oil warning neon light was lit for 30 seconds.

Does anyone really understand the operation of this ignition circuit?

Any feedback on the working of it would be appreciated.


Y Don't U send an interesting bul?

73 de John G8MNY @ GB7CIP


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