LETUS35A motor at DVinfo.net

Michael Fossenkemper · November 5th, 2006, 04:53 PM

I just had a weird thing happen today. I went to turn on my adapter and nothing, changed the batteries, checked the wiring, everything was good. So I took it apart thinking I might smell a burnt motor, nothing. So I tapped the motor and it started up. Do you think it was just stuck on a bad spot and the tap knocked it loose?

Bob Hart · November 8th, 2006, 10:22 PM

Michael.

No one has put their hand up so here is my guesswork. I am no electrical engineer and my competencies in this field extend only to personal endangerment.

My feeling is that your guess is the correct one.

The motor appears to be an extremely small simple DC motor which has what seems to be a hard chromed brush leaf spring (or blade) and commutator arrangement for a two maybe three pole setup. (My eyesight was too poor in the lighting to examine the motor more closely when the back came off it. I was mainly interested in not losing any tiny parts.)

It was purpose built for the vibration task, mobile phones I think.

A tiny speck of debris from normal operating wear might be all that is needed to stall the motor. Re-starting it like you did may see it working again without more trouble.

The brush arrangement is carried as an integration with the rear bearing and rear cover of the motor. The soldering tags are also part of this sub-assembly. The rear cover is retained by the traditional staking method with two bent tags on the main case can.

Over time, due to the vibration task given the motor, this rear cover might become loose in the back of the can. Quyen has encapsulated the back of the motor, the soldered joints for the wires and a portion of the wires themselves in a semi-hard clear adhesive.

My guess is this is a added precaution against mechanical and conductive failure due to vibration loosening the rear sub-assembly in the can.

November 5th, 2006, 04:53 PM	#1
Michael Fossenkemper Major Player Join Date: Sep 2005 Location: NYC, weeee. Posts: 417	LETUS35A motor I just had a weird thing happen today. I went to turn on my adapter and nothing, changed the batteries, checked the wiring, everything was good. So I took it apart thinking I might smell a burnt motor, nothing. So I tapped the motor and it started up. Do you think it was just stuck on a bad spot and the tap knocked it loose?

November 8th, 2006, 10:22 PM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,477	Michael. No one has put their hand up so here is my guesswork. I am no electrical engineer and my competencies in this field extend only to personal endangerment. My feeling is that your guess is the correct one. The motor appears to be an extremely small simple DC motor which has what seems to be a hard chromed brush leaf spring (or blade) and commutator arrangement for a two maybe three pole setup. (My eyesight was too poor in the lighting to examine the motor more closely when the back came off it. I was mainly interested in not losing any tiny parts.) It was purpose built for the vibration task, mobile phones I think. A tiny speck of debris from normal operating wear might be all that is needed to stall the motor. Re-starting it like you did may see it working again without more trouble. The brush arrangement is carried as an integration with the rear bearing and rear cover of the motor. The soldering tags are also part of this sub-assembly. The rear cover is retained by the traditional staking method with two bent tags on the main case can. Over time, due to the vibration task given the motor, this rear cover might become loose in the back of the can. Quyen has encapsulated the back of the motor, the soldered joints for the wires and a portion of the wires themselves in a semi-hard clear adhesive. My guess is this is a added precaution against mechanical and conductive failure due to vibration loosening the rear sub-assembly in the can. Last edited by Bob Hart; November 9th, 2006 at 09:23 AM.