SSG Minimizing Trigger Winding Losses

[nilrehob]

Hi everyone,

I have been looking at how to minimize the losses in the trigger winding in an SSG energizer:

https://sites.google.com/site/nilrehob/home/documents/SSG%20Minimizing%20Trigger%20Winding%20Losses.png?attredirects=0

https://www.youtube.com/watch?v=35AY5053C3Q
https://www.youtube.com/watch?v=rthoeuBtbz0
https://www.youtube.com/watch?v=17B_B6usv4E
https://www.youtube.com/watch?v=AcGiVRp4dp4

They all work differently and I have no favourite just yet.

/Hob

[MileHigh]

My suggestion is to look at the circuit in TK's MHOP series of videos.  When you use an op-amp for the trigger sensing you get two main advantages: 1) The trigger coil just becomes a pure-EMF source, it doesn't have to do any work to switch on the transistor.  There is never any energy in the pick-up coil because there is no current flow.  2) The switching speed is very very fast.  Therefore the transistor switches on and off instantly and no power is burned in the transistor.

Then you just choose the optimal base resistor to switch on the transistor based on the resistance and maximum current flow in the coil.

In theory, running the op-amp at a lower voltage allows you to lower the value of the base resistor, saving a tiny amount of extra energy.  It might not be worth it, you can do the calculations.  Ideally something like a low-power op-amp that can run off of a five-volt supply but I would have to check Digikey to see if they exist.

In the best case scenario, the current consumption of the op-amp would be very very low when not driving the transistor, and then just the base current plus a very very small delta when it is driving the transistor.

Once all that is done, the most critical thing is to decide on the timing for the energizing of the coil.  You could experiment with different ON times and record the RPM, input power consumption, and output power.  You have a bank of caps and a switchable resistor block.  So you use the bank of caps and the switchable resistor block to replace the charging battery so you can make very accurate output power measurements.

[nilrehob]

My suggestion is to look at the circuit in TK's MHOP series of videos.  When you use an op-amp for the trigger sensing you get two main advantages: 1) The trigger coil just becomes a pure-EMF source, it doesn't have to do any work to switch on the transistor.  There is never any energy in the pick-up coil because there is no current flow.  2) The switching speed is very very fast.  Therefore the transistor switches on and off instantly and no power is burned in the transistor.

Then you just choose the optimal base resistor to switch on the transistor based on the resistance and maximum current flow in the coil.

In theory, running the op-amp at a lower voltage allows you to lower the value of the base resistor, saving a tiny amount of extra energy.  It might not be worth it, you can do the calculations.  Ideally something like a low-power op-amp that can run off of a five-volt supply but I would have to check Digikey to see if they exist.

In the best case scenario, the current consumption of the op-amp would be very very low when not driving the transistor, and then just the base current plus a very very small delta when it is driving the transistor.

Once all that is done, the most critical thing is to decide on the timing for the energizing of the coil.  You could experiment with different ON times and record the RPM, input power consumption, and output power.  You have a bank of caps and a switchable resistor block.  So you use the bank of caps and the switchable resistor block to replace the charging battery so you can make very accurate output power measurements.

Thanks for the suggestions.
I will look at TK's MHOP once I'm done with SSG mods.
I have a new version coming up that I think is worth some attention,
but probably not until next week unless unexpected extra time shows up.

/Hob

[synchro1]

My suggestion is to look at the circuit in TK's MHOP series of videos.  When you use an op-amp for the trigger sensing you get two main advantages: 1) The trigger coil just becomes a pure-EMF source, it doesn't have to do any work to switch on the transistor.  There is never any energy in the pick-up coil because there is no current flow.  2) The switching speed is very very fast.  Therefore the transistor switches on and off instantly and no power is burned in the transistor.

Then you just choose the optimal base resistor to switch on the transistor based on the resistance and maximum current flow in the coil.

In theory, running the op-amp at a lower voltage allows you to lower the value of the base resistor, saving a tiny amount of extra energy.  It might not be worth it, you can do the calculations.  Ideally something like a low-power op-amp that can run off of a five-volt supply but I would have to check Digikey to see if they exist.

In the best case scenario, the current consumption of the op-amp would be very very low when not driving the transistor, and then just the base current plus a very very small delta when it is driving the transistor.

Once all that is done, the most critical thing is to decide on the timing for the energizing of the coil.  You could experiment with different ON times and record the RPM, input power consumption, and output power.  You have a bank of caps and a switchable resistor block.  So you use the bank of caps and the switchable resistor block to replace the charging battery so you can make very accurate output power measurements.

@Mileigh,

I can spin a rotor with a simple reed switch in series with a battery at extremely high RPM with even less amp draw. You're complex MHOP circuit looks like a real dog by comparison. My rotor goes at least ten times as fast for even less input with merely one componant.

[tinman]

@Mileigh,

I can spin a rotor with a simple reed switch in series with a battery at extremely high RPM with even less amp draw. You're complex MHOP circuit looks like a real dog by comparison. My rotor goes at least ten times as fast for even less input with merely one componant.

Reeds are good for low power motors,but once you start getting up in the higher power ranges, you start doing some arc welding with those reed switches,and they dont last to long.

Opto coupler and a fet is the way to go,where you power the opto coupler from the inductive kickback.