Hi,
Since I have a 400A 2kHz ye-ol Curtis that battery amps are limited (noticed
50A starting). I decided to try an additional choke in series with the
motor but inside the bypass contactor loop. Since T=L/R with the motor
inductance at 150uh and 58 milli-ohms, the time constant to pulse by pulse
current limit is quick thus limiting the duty cycle on start to 2.5ms. By
doubling the inductance or adding a 150uH choke, the start pulse width would
then be limited to 5ms. So I took a uWave oven transformer, angle ground
off the I bar on the E core and removed the coild and magnetic shunt. I
then put 6 turns of #2 welding wire on and MIG welded the I back on the E
for a 72uH choke measured. I then started the car again from a dead stop
and noticed 80A instead of 50 battery amps and it moved quicker into
operating range. I'll get another dead uWave and add another choke for a
total of 150uH. So if you have acceleration problems and you're duty cycle
limiting on start, try a choke or 2.
Best Regards,
Mark
_________________________________________________________________
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Since I have a 400A 2kHz ye-ol Curtis that battery amps are limited (noticed
50A starting). I decided to try an additional choke in series with the
motor but inside the bypass contactor loop. Since T=L/R with the motor
inductance at 150uh and 58 milli-ohms, the time constant to pulse by pulse
current limit is quick thus limiting the duty cycle on start to 2.5ms. By
doubling the inductance or adding a 150uH choke, the start pulse width would
then be limited to 5ms. So I took a uWave oven transformer, angle ground
off the I bar on the E core and removed the coild and magnetic shunt. I
then put 6 turns of #2 welding wire on and MIG welded the I back on the E
for a 72uH choke measured. I then started the car again from a dead stop
and noticed 80A instead of 50 battery amps and it moved quicker into
operating range. I'll get another dead uWave and add another choke for a
total of 150uH. So if you have acceleration problems and you're duty cycle
limiting on start, try a choke or 2.
Best Regards,
Mark
_________________________________________________________________
Need a brain boost? Recharge with a stimulating game. Play now!*
http://club.live.com/home.aspx?icid=club_hotmailtextlink1