Re: (ET) Mower motor problems

[David Brandt <ev_dave13 yahoo com>]

Not 100% sure, but the amount of lift the blades have can make a big 
difference in the noise they make.

David Brandt


--- On Tue, 11/3/09, John J Casey <jjcrmc verizon net> wrote:

> From: John J Casey <jjcrmc verizon net>
> Subject: Re: (ET) Mower motor problems
> To: "David Brandt" <ev_dave13 yahoo com>
> Cc: "Elec-trak" <Elec-trak cosmos phy tufts edu>
> Date: Tuesday, November 3, 2009, 10:11 AM
> I have a WH deck (ebay) with fat
> motors, baffles and the 'flower petal' reinforcement
> described by Jim.  Bought this deck with no cosmetic
> issues other than that the oem blades were beat up.
>  Sharpened blades, had all six motor bearings replaced
> and the deck ran without resonance and not much noise.
>  Sounded like a powerful vacuum,  A list member
> told me that WH still sold blades for this deck so I bought
> three....are a bit heavier but resemble the others and run
> with no noticeable resonance but are a whole lot noisier, a
> real racket. Any ideas?Thanks, Jack
> On Nov 2, 2009, at 9:29 PM, David Brandt
> wrote:
> Mine resonates as well.  The motors
> turn at slightly different RPM's due to the slight
> manufacturing differences between them.  the resonance
> you hear is called beating, where the frequencies drift
> slowly in and out of phase, and on mine, it actually shook
> one of the bolts almost all the way out of a support arm!
> 
> There isn't much you can do about it, it is due to the
> very slight RPM difference.  A stiffer deck would help,
> as would using lock nuts.  An anti-vibration gasket
> (say 1/8" thick rubber) between the motor and deck
> might also help, but adjusting the motor height would be
> difficult afterwards.  Me, I'd use locknuts and
> live with the vibration.  It isn't near as loud as
> an ICE mower.
> 
> David Brandt
> 
> 
> --- On Mon, 11/2/09, Stan Witherspoon <stwspoon speakeasy net>
> wrote:
> 
> From: Stan Witherspoon <stwspoon speakeasy net>
> Subject: (ET) Mower
> motor problems
> To: Elec-trak cosmos phy tufts edu
> Date: Monday, November
> 2, 2009, 12:21 AM
> I have been having
> mower motor
> problems. I have
> replaced the bearings, replaced one brush
> housing, had the same
> magnet in two different motors come
> loose, and now the
> magnet in one of my my replacement motor
> housing has come loose
> as well.  This is in less than
> 12 months and less
> than 10 mowings. I can't seem to get
> through a single
> mowing without having to fix something.
> 
> I realize these
> tractors are pretty old, but I would expect
> that stuff that gets
> fixed would stay fixed.  Is there
> anything I need to
> watch out for on the mower motors? I have
> been through the HSM
> and all of the on line archives. 
> My mower deck has a
> loud rhythmic vibration that resonates
> every second or so
> that goes away when the motors are loaded
> down, like when mowing
> thick grass. I have balanced the
> blades, replaced the
> blades, balanced the replacements,
> disassembled, cleaned
> and reassembled the mower deck and
> replaced the wiring on
> the mower deck. I also have new fiber
> washers and I torqued
> the blades bolts according to the HSM
> specs.
> 
> Any Suggestions?
> 
> Frustrated,
> 
> Stan
> 
> 
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