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Maha WgB70 conversion thread

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(@jpnovak)
Posts: 5
Member
Topic starter
 

Newbie here.   

Last year i picked up a Maha WgB70 roller set for cheap.   Took some time to save money and purchase the Yourdyno controller and DC supply.   This thread will track some progress and outline what is needed.   

I certainly have questions about the wiring and install.   This will be a repository.   

Let's begin!

 

 

first questions.   

  • I have opened the electronics compartment and found the DC supply and control board.   There are lots of connections going to this board.   So far I have traced the following
    • AC input - this is straight forward.   Will wire to US 220V-30A plug.  
    • strain gauge 
      • wiring
    • cooling fan for retarder
      • Can I use an I/0 to drive this fan?  I suppose I need to check if it will run on the 5V output.   
    • retarder connection
      • The 4 coils have wires that merge inside a junction box.   I have not removed the cover to see what parallel-series connections are made. 
      • any suggestions for the best way to wire? 
      • How much voltage is each coil supposed to be rated for?  This way I can figure out what is needed to get to the target 96/192V rating.  
    • There are 8 additional wire bundles that go across to the rollers.   
      • I have no idea what they do.   Anyone have a wiring diagram that i can follow?   
    • Speed reference
      • I need to add the speed sensor wheel and actual sensor.   
      • Does this get mounted to retarder or rollers?  
    • RPM
      • I plan to add an RPM inductive pickup.   
        • high tension wire inductive pickup is straightforward.   
        • Does anyone have suggestions for one that will work with COP setups?
    • Anything else I am missing?  

 

Is it possible to upload photos?  Or do I need to link from external site?  

 

Thanks

Jamie

Austin, TX, USA

  •  
 
Posted : 02/01/2025 3:43 am
Mr Peter reacted
(@jpnovak)
Posts: 5
Member
Topic starter
 

FYI.   I just found an online manual for this dyno.   It was also sold under SnapOn brand.   Quick read might answer some of my questions about wiring.   

 

https://www.snaponequipment.com/common/serviceparts/mahaasmhp.pdf

 

 

 
Posted : 02/01/2025 2:52 pm
(@jpnovak)
Posts: 5
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Topic starter
 

Reading through the manual each coil is rated 96V.   In this case I am planning 2 series - 2 parallel connection to give me 192V total.   will plan to pair the coils 180deg across for parallel.   

 

Any Concerns here with this proposed setup?  

 

I also found that there is an integral speed sensor.   In this case, I answered a question above about mounting the external speed sensor.  I will just use the existing one.   I will also use the integrated temperature sensor on the eddy current drive as AUX in.   Hoping I can set software limits based on temperatures.   I will just need to figure out calibration factors for each of these sensors.   

 

 
Posted : 02/01/2025 3:55 pm
(@jpnovak)
Posts: 5
Member
Topic starter
 

I spent some time going through the coils today.   They are already wired 2P-2S.   Then I started questioning my electrical math.   Each coil rated 96V.   Connecting in parallel does not change the voltage rating.  It just divides the coil resistance by half.   Then the two sections in series will add voltage to get 196V and meet my target.   The two coils in series then restores the wire resistance back to original.   Is my logic correct?   

 

 

 
Posted : 03/01/2025 2:31 am
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