Replacing Markon SL105 AVR with SX460

[Tasemu]

Hi all, i promised i'd be back with results so here I am! I found this schematic (attached to post) online for a very similar markon generator head and figured that if I disconnected and isolated Z3 and Z2 from the rectifier then it should no longer be supplying the slip rings with a voltage. After doing this I installed the F1 and F2 cables from the slip rings to the old AVR and connected them to the new SX-460, i also used wago connectors to tee off the live and neutral from one of the generator outlets to supply the SX-460 with power and voltage sensing.

When starting the engine nothing exploded and i was getting around 120v @ 42hz. I slowly increased the speed of the engine until the speed bolt (pictured) topped out at about 49.6hz. I then slowly raised the voltage potentiometer on the SX-460 until I got a clean 230vac from the outlet at no load.

I have included a video of the results, and this appears a success at first glance but i'd appreciate a sanity check on my methods, and also one question. Is it normal that my little beta engine for the generator only reaches a top speed of ~50hz? The bolt wouldn't go any further.

 

Thanks so much for all the help so far and any answers to my above 2 questions!

 

Results Video:
 

 

[BEngo]

Next thing is to check the regulation.

 

You need to increase the load in steps,  to near full power, checking and adjusting the output voltage  and frequency at each step.  A fan heater is a good tool because they usually have various heat settings. Best thing I'd to just run through, measuring, and then decide what output power you want to set it up at, with some idea then where it will be at no load and full load.

 

You may expect to find that at full output the voltage is at the low end of the range and at low output it is in the high end of the range.  The official UK ac power supply limits are something like 236 to 254 V.  AC

 

   The regulated speed of the Beta will depend on how it has been set up.  I would certainly expect more than 49 Hz to be available at no/low load.  The speed regulation will inevitably have some droop, so if you can't get 50+ Hz at no load you will be looking at ~45 Hz or less at full load.

 

N

 

  

[Tasemu]

2 hours ago, BEngo said:

Next thing is to check the regulation.

 

You need to increase the load in steps,  to near full power, checking and adjusting the output voltage  and frequency at each step.  A fan heater is a good tool because they usually have various heat settings. Best thing I'd to just run through, measuring, and then decide what output power you want to set it up at, with some idea then where it will be at no load and full load.

 

You may expect to find that at full output the voltage is at the low end of the range and at low output it is in the high end of the range.  The official UK ac power supply limits are something like 236 to 254 V.  AC

 

   The regulated speed of the Beta will depend on how it has been set up.  I would certainly expect more than 49 Hz to be available at no/low load.  The speed regulation will inevitably have some droop, so if you can't get 50+ Hz at no load you will be looking at ~45 Hz or less at full load.

 

N

 

  

 

Hrmm. the only way i know to adjust the engine speed was from this bolt that pushes the adjuster on the engine. I've had to push this the whole way in, you might hear the engine sounding quite fast on the video. Perhaps i'm adjusting the speed from the wrong control?

 

EDIT: The bolt in question is the steel un-painted one which moves the larger red leaver under the shorter red one.

3 hours ago, BEngo said:

Next thing is to check the regulation.

 

You need to increase the load in steps,  to near full power, checking and adjusting the output voltage  and frequency at each step.  A fan heater is a good tool because they usually have various heat settings. Best thing I'd to just run through, measuring, and then decide what output power you want to set it up at, with some idea then where it will be at no load and full load.

 

You may expect to find that at full output the voltage is at the low end of the range and at low output it is in the high end of the range.  The official UK ac power supply limits are something like 236 to 254 V.  AC

 

   The regulated speed of the Beta will depend on how it has been set up.  I would certainly expect more than 49 Hz to be available at no/low load.  The speed regulation will inevitably have some droop, so if you can't get 50+ Hz at no load you will be looking at ~45 Hz or less at full load.

 

N

 

  

 

No idea why, but when running with a ~2kw load the voltage climbed from 230v to 236v... The hz went down to 48.7hz. But clueless on that. Currently using the air fryer to heat some chicken wings to see if the engine overheats with the current rpm required to get 50hz.

Edited January 5 by Tasemu

[cuthound]

3 hours ago, BEngo said:

Next thing is to check the regulation.

 

You need to increase the load in steps,  to near full power, checking and adjusting the output voltage  and frequency at each step.  A fan heater is a good tool because they usually have various heat settings. Best thing I'd to just run through, measuring, and then decide what output power you want to set it up at, with some idea then where it will be at no load and full load.

 

You may expect to find that at full output the voltage is at the low end of the range and at low output it is in the high end of the range.  The official UK ac power supply limits are something like 236 to 254 V.  AC

 

   The regulated speed of the Beta will depend on how it has been set up.  I would certainly expect more than 49 Hz to be available at no/low load.  The speed regulation will inevitably have some droop, so if you can't get 50+ Hz at no load you will be looking at ~45 Hz or less at full load.

 

N

 

  

 

The voltage limits for the mains in the UK is +10% (253 volts) and -6% (216.2) following the harmonisation of our original 240 volts supply with Europe's original 220 volt supply to a nominal 230 volts.

 

https://www.legislation.gov.uk/uksi/2002/2665/regulation/27/made

Edited January 5 by cuthound
Clarification

[Tasemu]

Just an update:

Since installing the SX-460 as stated through this thread. I've managed to swap out my cheapo battery charger and inverter for a new victron multiplus that I bought a year ago but was unable to use with the generator and unable to return I am now able to charge at 70a with no problem instead of the original maximum of 17a i was getting previously, what a difference! On top of that the washing machine that came with the boat also now works happily with the new cleaner voltage and frequency, I've just finished my first load of washing not in a laundrette and hung it to dry in front of the rayburn. I started this over a year ago and it has actually spanned a few threads here over that time. I've finally been able to tick this off my list and I couldn't be happier.

 

EDIT: Gettin all bloody emotional up in here haha 😅

Edited January 15 by Tasemu

[Tony Brooks]

I bet you could not, and well done for persevering. Seems like an excellent final result.