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://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=35AY5053C3Q)
https://www.youtube.com/watch?v=rthoeuBtbz0 (https://www.youtube.com/watch?v=rthoeuBtbz0)
https://www.youtube.com/watch?v=17B_B6usv4E (https://www.youtube.com/watch?v=17B_B6usv4E)
https://www.youtube.com/watch?v=AcGiVRp4dp4 (https://www.youtube.com/watch?v=AcGiVRp4dp4)
They all work differently and I have no favourite just yet.
/Hob
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.
Quote from: MileHigh on March 27, 2015, 02:47:06 PM
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
Quote from: MileHigh on March 27, 2015, 02:47:06 PM
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.
Quote from: synchro1 on March 27, 2015, 04:38:54 PM
@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.
Quote from: tinman on March 27, 2015, 07:47:08 PM
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.
@Tinman,
Right. I'm not at all impressed with the rotor speed of TinseKoala's MHOP. I wonder how the top end of the MHOP really compares to some of the other configurations? Looks like a weak "Slow Poke" circuit to me so far.
One thing that TK's rig does that is very good is squae up the drive signal. That is good for efficiency. Other amplifier methods such as using an optocoupler can achieve similar ends. Mechanical switching such as with a reed suffer rapid wear-out especially if arc suppression is not employed.
Quote from: nilrehob on March 27, 2015, 03:51:31 PM
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
I will also just state the obvious that I did not state. There is a very good chance that a MOSFET will do just as good a job as the transistor. With an op-amp and MOSFET combination you can probably reduce the average power required to control the timing of the switching function for the main drive coil to a few milliwatts. So you effectively nearly eliminate the overhead for the timing and switching and can then focus on the power in vs. power out for the main drive coil. As we know, the shorter the time allocated for energizing the coil, the lower the resistive losses to heat.
Quote from: synchro1 on March 27, 2015, 04:38:54 PM
@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.
Just like Mark said about you in another thread with respect to him, for both your comments here, you are just trolling me.
Quote from: MileHigh on March 28, 2015, 09:39:28 AM
Just like Mark said about you in another thread with respect to him, for both your comments here, you are just trolling me.
How fast is it? Have you or anyone else tested it for speed?
That other Airhead denies pressure causes heat. You're both good at just blasting it out your asses under pressure.
Quote from: MileHigh on March 28, 2015, 09:37:30 AM
I will also just state the obvious that I did not state. There is a very good chance that a MOSFET will do just as good a job as the transistor. With an op-amp and MOSFET combination you can probably reduce the average power required to control the timing of the switching function for the main drive coil to a few milliwatts. So you effectively nearly eliminate the overhead for the timing and switching and can then focus on the power in vs. power out for the main drive coil. As we know, the shorter the time allocated for energizing the coil, the lower the resistive losses to heat.
Certainly for things switching at slow repetition rates up to 10's of kHz it is going to be rare that a BJT will be more efficient than a MOSFET.
Quote from: synchro1 on March 28, 2015, 10:09:47 AM
How fast is it? Have you or anyone else tested it for speed?
That other Airhead denies pressure causes heat. You're both good at just blasting it out your asses under pressure.
Are you heating your home with your coffee table yet? Are you making diamonds with it yet? I won't tell DeBeers.
Even using the very pedestrian Op-Amp that TK pulled out of the drawer, the comparator circuit in the MHOP has much better timing response and stability than a reed switch. It has the additional benefit of not suffering contact arcing and wear out. The single disadvantage of the circuit is that it requires bias voltage whereas a reed switch is powered by the mechanics of the system.
Well guys, did any of you really look into any of my videos?
Did any of you respond to the content of my videos?
Are any of you for real or are You all just trolls?
You really fucked up this thread really fast.
Thanks!
Ill start a new thread with my next circuit so You can continue trolling this one.
/Hob