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RE: Pulling Amps etc.
- Subject: RE: Pulling Amps etc.
- From: "Naugler, Steve" <SNaugler Rodel com>
- Date: Mon, 4 Jan 1999 13:21:08 -0500
- Sender: owner-elec-trak cosmos5 phy tufts edu
Please excuse me for repeating: Inductive sensors do not work on
current. The Snap-On clamp on current sensor had to have been a hall
sensor, probably made for Snap-On by F.W. Bell. (I have a F.W. Bell clamp
on hall effect labeled Allis Chalmers.) Hall effect sensors are very easy
to use, but you must properly zero thhem before each use when used for DC
With respect to the current numbers measure by Sarah: Wow. I had
not expected to see currents that high. The E15 has a 1.5 kw motor.
watts/36V)/0.85 efficiency)=49A The E20 has a 1.8 kw motor >> 59A. (Motor
kw per Bill Gunn at Technical Service.)
I had not used my current sensor to measure the running currents,
but I will after I get fresh batteries sometime next spring.
-e mail address: snaugler rodel com
> From: Sarah Kanary[SMTP:kanarys zbzoom net]
> Sent: Sunday, January 03, 1999 3:12 PM
> To: Elec-trak
> Subject: Pulling Amps etc.
> Hi group!
> First time posting to this site, so bear with me please. Allow me to
> comment on the following issues:
> "pulling amps"
> The following readings were taken on my E20-CA model [8 speed, 3 armature
> resistors]. It has the lower profile Firestone Tires, which does reduce
> ampere draw somewhat at the traction motor.
> Mowing 3 to 6 inch high grass, relatively level, in "L" range,
> approximately100-125 A. This reading was taken at MS-1, using a Snap-On
> automotive inductive ammeter, used for diagnosing automotive & truck
> starters, up to 24VDC.
> Note also, that the current sensing feature on this tractor has been
> defeated, as I am the primary user. Cruise control was used to guarantee
> 4th speed operation.
> Clinbing my "steep as a horse's nose" yard, the ampere draw can easily
> exceed 300A while mowing. Using this tractor at my place of employment
> wrecker has shown short term draws exceeding 500A, when towing a fuul
> van or 4wd pickup into the garage. This operation is performed in D2 to
> limit wheelspin. Our parking lot is gravel! Hope this helps!
> On the subject of the "spastic traction motor": Take that rascal out of
> service now! Bill Gunn of Tech Parts filled me in on one of the assembly
> line problems built into some of these motors. Seems that the screw
> the "shunt" lead to the brush rigging was never tightened properly at the
> factory. Loose high current connections result in heat, and this usually
> fries out the brush rigging AND THAT AIN'T CHEAP!
> Short brushes aggravate the heat & fry problem, so definitely get another
> Bearings are industry standard 6203 & 6205, get the sealed ones, not
> shielded. Biggest problem is getting the pulley off without trashing it!
> As you have seen, Iexpect a lot from my relic and it usually does not
> disappoint. I've found areas I'd like to toughen up, but more on these
> Randy Kanary
> kanarys zbzoom net