Re: [electricboats] Motor Mount and Thrust Plate design - hoping for feedback

Only 3/8 bolts to hold the motor?   I think you'll be fine.   My ME1616 motor is held with four 5/16 fasteners.  It was fine.  I tightened mine with a quick clamp pulling the motor pulley to snug the belt while I tightened the mounting bolts.  It doesn't take a crazy lot of tension with the toothed belts. 

I don't think you need the idler and it is an extra part and an additional wear point for the belt.   It might be useful if you have a problem with engagement of the toothed belt over the small pulley.  But unless you are running something like a 20 and a 100 tooth pulley you will likely be well within spec for engagement.  I am running 20 and 60 for 3:1 reduction and engagement is fine. 

That 1/2 stainless mounting plate seems pretty extreme.  How are you machining that?  It will be quite tough unless you do it with a water jet?  I used 3/4 aluminum because it is easy to work with, properly rigid, and thick enough that I could countersink all the fastener heads for a flush face where the belts ride.   But I am not in a challenging corrosion environment. 

What are the specs on your installation and on the boat?   Motor size, battery size, boat type, loa, lwl, displacement, etc...

I have been meaning to post an end of season review of my experience with my electric drive.  I'll see about that soon.  

Thanks, Dan Pfeiffer

On 2021-12-28 5:32 pm, Steven Borg wrote:

Thanks, Dan!  I appreciate the comments. Very much!

You reminded me of a question I forgot to ask about belt tightening. Thank you!

My current plan is to mount a free spinning, 2" idler on one or both sides of the belt. I put two 1/2" slots to accept the bolt. Today, the 30mm wide, 8mm pitch belt slides on my prototype fairly tightly, then I can tighten with the idler.

However, you recommend using slotted holes for the motor mount. I considered that, and it would likely be ideal, since I wouldn't need an idler - saving me both space (I could bring the two gears closer together), and efficiency of having a bend in the timing belt (not to mention the additional wear).  What kept me from doing that is that the motor is 120 pounds and I was worried that the weight and vibration would eventually 'wiggle' the motor down, loosening the belt. This is especially true since I'm having to mount only a single face of the motor (at least that's the current plan).  (Plus, the bolts are only 3/8" holding in the motor.)

Am I being overly concerned about the bolts loosening and the motor slipping down?  I'd love to have slotted mounts, but I'm nervous!  

Thanks again, Dan!  I really appreciate your help. Especially the drawing of your solution!