HPM5000B Noise

[T27_478]

Hello All,

I've recently completed a inboard sailboat converstion to electric using a combination of HPM5000B and HPC300 motor and controller respectively. Although everything works fine and powers the boat with authority I was hoping for a quieter ride. I've got the motor mounted on neoprene to help absorb vibration, I'm really concerned about the whir from the motor that seams to resonate in the fiberglass hull.  I have read on other sites that it may have to do with the tuning of the controller to the motor but I'm not sure where to even start. I've also read on here that it may be an issue with GM switching the heavy phase wires. In either case I'm hesitant to start playing around in fear of breaking something that's currently working almost perfectly.

[Morgen 3Eman]

May I ask what you mean by "I've got the motor mounted on neoprene to help absorb vibration"?  My mind's eye keeps seeing a motor hung by bungee cords:)

Dennis

[T27_478]

The motor is mounted to an aluminum plate via the normal M8 bolts. I have neoprene washers at this connection to help isolate vibration from the motor to the plate. The plate is then connected to the fiberglass engine supports via  an A-Frame for stability. I have more neoprene washers between this frame and the original fiberglass engine support from the old ICE. The GM motor is certainly not floating in the air somehow, is securely fastened to the boat, I've just included some cushion to help soak up vibration.

The noise seems to be coming from the motor, it increases proportionately in volume and frequency as the rev's increase and sounds like an electric whir which I cannot isolate out with dampers as I can vibration. My research up to this point is heading me in the direction that the phases/sensors are hooked up wrong (I followed the diagrams on the GM site for Green-V, Blue-U and Yellow-W for the labels on the controller). Alternately I understand that some of the noise can be calibrated out as a timing issue in the controller.

I'm very much a novice on these things and am only knowledgeable enough about electronics to be dangerous, thus asking here.

[Morgen 3Eman]

So you just have a neoprene washer between the motor mount and the Al plate, with a bolt thru it? Any chance you could show us a picture?

How is the driven shaft connected to the motor output shaft?  Is this an inboard installation?

Dennis

[T27_478]

Here is a quick diagram of the setup. I doubt the issue is the vibration isolation between the motor and the boat. The problem is the motor making a harmonic sound as a result of calibration between the motor and controller.

[Morgen 3Eman]

As you have them installed, the neoprene washers are acoustically short circuited by the bolts.  If you Google something like "electric motor vibration mount"  you will find images of devices that have bolts bonded to the ends of a block of polymer.  That design works quite well, but  I suspect you will still be able to hear the motor.  I have no idea what the current cost is, but they used to be pretty cheap.  If the Al structure is folded sheet , that may also be acting as a sound board, amplifying the noise level...

Dennis

[Bikemad]

Perhaps some of the noise is being generate by the chain and sprockets, how does the motor noise compare to this one?

Alan
 

[T27_478]

The motor is quite a bit louder, which I attributed to the fact that it is loaded. I've ordered some different stud type mounts that should provide better isolation and eliminate the "short circuit". I would love to enclose the motor and gear system with some sound proofing but am concerned about head. Perhaps I shouldn't have cheaped out and gotten the liquid cooled version, then heat wouldn't be a concern and I could box the thing up in some foam to eliminate the noise. I just don't like the idea of running water INSIDE of the boat unless I have to, god forbid the fittings on the motor fail and I  find only a mast sticking out of the water.

[T27_478]

Just as an update, I've ordered some proper mounts as stated and will install in the next week. From other forums the chopping type noise I'm hearing is likely the motor itself since it is working off of a PWM signal it acts as a speaker. I think the mounting plate as others have mentioned is acting like a sound board making things louder. My understanding is that since I'm using a square wave controller the noise is not going to to away, this may be an un-told advantage of a sine-wave controller as it smooths out the signal and the motor doesn't pound. Has GM done any testing on the sound difference between their new sine-wave controllers and the traditional ones?