GoldenMotor.com Forum

Hi Terry,

I'm not familiar with the EZKontroller settings, so I don't know what gear/speed options are available or how they might affect the low rpm torque/current. It might be worth contacting your supplier direct and explain your low power/rpm problem to them to see if they have a simple solution.

If you don't have a switch to select different gears, try to make sure the default gear is set to the highest available and see if it makes any difference.

Are there any error codes (blinking LED) on the controller? If there are, check out page 9 of the User Manual to determine what's causing the error.

If you have (or are able to borrow for testing) a smaller pitch/diameter prop, it would be very useful to see what difference it makes to the rpm, current draw and the maximum boat speed at full throttle.

Hopefully you will be able to get it much closer to the expected ~5.5-6 knots. (1.34 x the square root of the waterline length of boat in feet.)

Alan
 

Hi Tez andto the forum.

I have very little knowledge of the EZ range of controllers, but I suspect that you may well have something set incorrectly in the controller settings if it's only drawing 25A at 700rpm with full throttle.
According to the User manual, the maximum bus current for the B721000 controller is 500A!

Check the Settings for the controller regarding the Max phase current(A), Max rotor speed(rpm) and Max bus current(A) etc. to see if anything is obviously wrong there.

Whilst belt reduction and/or a smaller propeller with less pitch may well be required to improve the efficiency of the motor, I would still expect the bus current to be a huge amount higher than 25A @ 700rpm if the motor is struggling with incorrect gearing/prop size etc..

Perhaps the motor or controller is simply getting too hot and is automatically reducing the current to prevent overheating, but I don't know for sure if this is the default action with the EZkontrol controllers.
If the current draw from cold is significantly higher, then this could be what's happening.

Hopefully, you will be able to monitor their temperatures using the App to see what is happening.

Do you have liquid cooling installed for both the controller and the motor?

Did the original diesel motor drive through a gear reduction unit? If so, what would the original propshaft rpm have been at maximum boat speed?
According to the Dynomometer figures, the HPM-10kW motor achieves maximum power and maximum efficiency @ just over 3,800 rpm, but I would aim for a gear reduction and/or smaller prop etc. that would allow the motor to run somewhere between 3,000 and 3,500rpm at maximum cruising speed.

Alan
 

I have just been looking at another post showing the inside of the air cooled motor and one of the photos shows four round (threaded?) holes on the rotor:



I suspect that these holes in the rotor disc will be threaded, and would be used (along with a special puller) to pull the rotor disc off the splined motor shaft.

If the rotor disc has been pushed onto the shaft too far by installing mounting bolts that were too long, then you may be able to use some suitably threaded rod and nuts in conjunction with a solid piece of hardwood (or steel box section) across the end of the motor shaft to pull the disc back slightly:



If (after removing the circlip on the motor shaft) the motor cannot be dismantled easily, you may be able to use a simple puller (similar to the one shown above) with the threaded rod screwed into the mounting bolt holes on the front casing to gently pull the housing/bearing off the shaft.

If the centre of the shaft end has a threaded hole for a bolt, you should be able to use a piece of threaded rod and suitable lengths of wood or piece of metal tubing with a large washer and nut to gently pull the motor shaft back through the bearing and front housing again:

   

Hopefully you will be able to sort the problem with this information.



Alan

EDIT: Additional attachments added to post.

Hi, I’m a new member.
I have a Golden Motor 5kW BLDC motor that has mechanically seized after a few hours of use.
It’s completely blocked (cannot turn by hand). Bearings are OK, but I suspect a rotor–stator contact or magnet shift.
Can someone confirm the correct internal structure (axial flux) and provide disassembly instructions or photos?
Thanks!

Hi Joe andto the forum.

Hopefully you will find lots of useful information on this forum.

Alan