FETs and RoF drops

[pestobanana]

So I've installed a number of FETs, and I've experienced RoF drops every time I install a non AB FET, but I never have any problems on a FET with AB. Maybe it has to do with the non AB FETs I've used, but has anyone experienced similar problems? I'm not convinced I suck that much at soldering.

Gun #1:
Gate MERF 3.2 - no problems 31 RPS

Gun #2:
Infected Armory AB - no problems 33 RPS
Switched to PicoSSR2 - dropped to 24 RPS

Gun #3:
No FET - 37 RPS
Installed PicoSSR2 - dropped to 25 RPS, fried very quickly
Rewired to no FET - 37 RPS
Installed Bravo Basic FET - dropped to 27 RPS

Gun #4:
No FET - 34 RPS
Installed PicoSSR2 - dropped to 27 RPS

Gun #5:
Gate NanoAB - no problems, 27 RPS

[KenTsui]

What's the setup of your gun?

[pestobanana]

Originally Posted by KenTsui

What's the setup of your gun?

Gun #1: 18:1 gears, M120, Lonex A1 motor, 11.1V 3.3Ah 25C battery
Gate MERF 3.2 - no problems 31 RPS

Gun #2: 16:1 gears, M100, VS High Torque motor, 11.1V 1.3Ah 25C battery
Infected Armory AB - no problems 33 RPS
Switched to PicoSSR2 - dropped to 24 RPS

Gun #3: 13:1 gears with 2 teeth SSed, M90, Lonex A1 motor, 11.1V 1.3Ah 25C battery
No FET - 37 RPS
Installed PicoSSR2 - dropped to 25 RPS, fried very quickly
Rewired to no FET - 37 RPS
Installed Bravo Basic FET - dropped to 27 RPS

Gun #4: 18:1 gears, M90, Lonex A1 motor, 11.1V 1.3Ah 25C battery
No FET - 34 RPS
Installed PicoSSR2 - dropped to 27 RPS

Gun #5: 18:1 gears, M100, Lonex A1 motor, 11.1V 1.3Ah 25C battery
Gate NanoAB - no problems, 27 RPS

[pestobanana]

Nobody's had this problem before?

[ThunderCactus]

it's pretty well impossible actually. Given the nature of the electronic device you're installing versus the stock trigger system....

What's your wiring diagram?

[Stealth]

Get a wattmeter which would tell you how many amps you're pulling.

You're counting ROF with your chrony or using sound?

John

[pestobanana]

I've done the basic install where I solder the two trigger wires together to one contact and the signal wire to the other contact, as well as rewiring the motor straight to the battery, two signal wires at the contacts, one going to the trigger labelled spot on the PicoSSR2 and the other signal wire on to the motor negative spot. I got RoF drops both ways. Bravo FET was installed using the first method. Infected Armory FET was also installed that way. Gate NanoAB and Merf 3.2 were installed with both wires going straight to the motor and two signal wires going to the contacts.

John, I actually meant to order one but I guess I forgot to include it in my order, is it too late to add it in?
I'm measuring with my Xcortech.

[Stealth]

Originally Posted by pestobanana

I've done the basic install where I solder the two trigger wires together to one contact and the signal wire to the other contact, as well as rewiring the motor straight to the battery, two signal wires at the contacts, one going to the trigger labelled spot on the PicoSSR2 and the other signal wire on to the motor negative spot. I got RoF drops both ways. Bravo FET was installed using the first method. Infected Armory FET was also installed that way. Gate NanoAB and Merf 3.2 were installed with both wires going straight to the motor and two signal wires going to the contacts.

John, I actually meant to order one but I guess I forgot to include it in my order, is it too late to add it in?
I'm measuring with my Xcortech.

I just came back from the post office and dropped off your order.

Try measuring through sound. Get a mic and download Audacity. Do a 2-3 second burst and count the peaks.

By measuring through sound, you're removing any sources of error from feeding or the chrony.

John

[ccyg8774]

Originally Posted by Stealth

Get a mic and download Audacity.

Thanks, I was looking for a program like that.

[pestobanana]

Originally Posted by Stealth

Try measuring through sound. Get a mic and download Audacity. Do a 2-3 second burst and count the peaks.

By measuring through sound, you're removing any sources of error from feeding or the chrony.

John

Every time I had a RoF drop I noticed it audibly first and then confirmed with my chrono.

I made sure my chrony was fine testing my SR16 a few days ago, I got the same result with both audacity and the chrony. I don't believe the differences in RoF are due to misfeeding, because when I experienced misfeeding my chrono would tell me I was shooting at half the speed I actually was.

[ccyg8774]

Do you have a multimeter to test the voltage across the two wire terminals that goes to the motor, when the motor is unpluged and trigger being pulled?

If this voltage is significantly lower than the voltage measured directly from the battery + and - terminals, then something is wrong in the electrical part. If not then the problem is most likely in the mechanical part.

I do this whenever I installed a new MOSFET (especially the homemade ones), to confirm that the MOSFET is working properly without having to put everything back and test fire. Most of the times the voltage difference is less than 0.1V.

[pestobanana]

Originally Posted by ccyg8774

Do you have a multimeter to test the voltage across the two wire terminals that goes to the motor, when the motor is unpluged and trigger being pulled?

If this voltage is significantly lower than the voltage measured directly from the battery + and - terminals, then something is wrong in the electrical part. If not then the problem is most likely in the mechanic part.

I do this whenever I installed a new MOSFET (especially the homemade ones), to confirm that the MOSFET is working properly without having to put everything back and test fire. Most of the times the voltage difference is less than 0.1V.

Hmmm, good suggestion. I'll try that next time I go home, I don't have a multimeter with me at school.