MAS48-0-Heli Cutout

[stall warning]

I have 48-0-H controller in a Logo, 6 Lipo Cells, 600W 12 Pole outrunner.
Everything new except the transmitter which is currently used in a Raptor.
I'm only at the point where I'm bench testing and hovering 3-4 ft off the ground
to adjust trims etc. 2 to 3 times per battery charge I get a brief shutdown.
I'm not getting a glitch, no twitch in the servos. I've tried 5 and 6 volt receiver
packs and the usual troubleshooting, connectors, solder jounts etc.

When I get this shutdown, the FDR shows a large spike in current and the
resulting drop in battery voltage. The rotor speed takes a nosedive. The motor
sounds as if it was "braked" for a second. The controller appears to
immediately go back into soft start mode. By this time I've done my mini Auto
and then cut power to prevent it from going back up. This will happen in
normal or Gov mode. While bench testing this, I can see the degree of
brake varies. It can run for 5 min before it happens. The controller is
barely warm as it's drawing about 450Watts at 9 degrees pitch.

I've not seen this in other brushless systems. If it is not a possible failure
mode of this controller, my best guess is that it is losing control.

Prog Box V01
type: Heli Controller: M-48-0-H Heli Mode: Constant or Normal
Timing 15deg Freq: 16kHz Acceleration: Soft Acc type: LiPo
#Cells: 6 Lipo Cutoff: 3.0 Init Point:Auto End Point: Auto
Throttle Curve: Linear Rotation:Right Timing Mon: On

[kyna]

Stall Warning,

It sounds as though you are having a premature low voltage cut-off. This situation is too complicated to try and solve in this forum. Please contact us at 480-726-7519 so we can determine where the problem might be, and get you flying.

Best Regards,

Kyna Veatch
Office Manager
Hacker Brushless USA

[stall warning]

I did another bench test. Changed freq to 8kHz and moved the timing back
to 10deg, that's 5 less than recommended for this motor.
Ran out the pack without a shutdown.
Only current spikes I saw were during spoolup and spooldown. No sign of
braking or rapid rpm drop. The slowdown at the end of the pack was smooth.

I don't know if it's solved, will have to fly it to be sure.

Thanks,
Ron

[teamdavey]

I would be very interested to hear the outcome of this. I had a very similar problem that seemed to be cured by changinh to a better battery pack. I certainly looked like the ESC was "losing" the timing for some reason.

Jim Davey

[stall warning]

No problems since moving the timing back.

Ron

[teamdavey]

Thanks.

I ended up running my Axi at 30 deg and have flown at 25 without problems. My initial findings were that more was better but that may have been confused by the wrong cells - weird.

I have never had this problem with any other combination.

Jim Davey