Hi Brad, Thanks for the details and the video link. It was okay for me that Q2 did not receive battery voltage, only its role was not fully clear. Now I understand how it was intended, I have redrawn your schematic to a style which makes it a better understandable schematic for me. If you disagree with it, please tell. So as you wrote on Q2: "it is used as a switch to complete the circuit of L1 (trigger coil) from the base to the emitter of Q1 and to allow L1 to become open when L2 does". Well I think somehow the switch-on moment for Q2 must come a little bit earlier or at the same moment in time rather than a bit later than that for Q1 to fulfill the expected task a 100%, right? This would need a dual channel scope comparison of the two collector waveforms just around the switch-on moments. Poppy mentioned in his video that the run coil had 800 turns and the trigger coil had 400, your schematic indicates equal number of turns for the two coils and this latter sounds better for me because less voltage is induced across a coil with less number of turns and this reduces charge power. Poppy also wrote on your forum that the average input current draw was 37.6mA and the output charging current was 11.2mA at one test. I think an improvement in the charge power could be had by using a higher Beta transistor type at both Q1 and Q2 because a 2N3055 has low Beta and may need a few mW base-emitter power to switch on and that power is taken away from the induced voltage/current in L1. A better transistor type is for instance ZTX853 (100V, 4A, see data sheet here: http://www.diodes.com/datasheets/ZTX853.pdf ) and costs about 1 USD at Digikey ( http://www.digikey.com/product-detail/en/ZTX853/ZTX853-ND/92592 ) of course there are similar high speed switching types with high Beta and very low saturation collector-emitter voltage but their price may also be higher. A 2N3055 at Digikey now is 1.82 USD. (A notice with these better transistors: you cannot abuse them as much as you "got used to" abusing a 2N3055 type, they need more attention.) Further improvement may be had by shunting the trimmer potmeter with a capacitor, this can reduce the AC voltage drop due to the spike current but tests are needed of course. Would like to know whether you actually managed to measure the efficiency of this setup (output torque/input electric power) or you simply draw this conlusion (one of the most efficient pulse motors you designed) on comparison to other setups how good this one drained and charged batteries? Just to know what level of efficiency we are to improve. Thanks, Gyula Hi Gyula
Q2 is not suppose to recieve any battery voltage.To understand how this circuit work's,it would be handy to have the standard SSG circuit next to you.
In the standard SSG ,L1 is always coupled together via (what would be) VR1 R2 and D1. In this circuit Q2 is used to decouple L1.
In this circuit the inductive kickback travels through D4 when Q2 switches off and decouple's L2.Only B1(charge battery)recieve's this charge.At the same time Q2 switches off,and L1 is decoupled.This sends the inductive kickback of L1 through D3 and into B2(run battery).As both windings and wire size in L1 and L2 are the same,the charge that B1 recieve's is determond by the value of R1 and VR1.
Q2 is just used as a switch to complete the circuit of L1(trigger coil)from the base to emitter of Q1,and to allow L1 to become open when L2 dose.
As far as which way the coil should be placed,well it will work either way.But it will perform better with the coil core parallel to the magnet's-as per standard pulse motor configuration.
Here is a replication of the circuit that one of my forum members built.
http://www.youtube.com/watch?v=5HwUuPQn2W8
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Topic: Pulse motor circuit's and design's (Read 27738 times)
