SMT Motor Noise Analysis

Customer send a complaint of SMT motor noise problem

We set up a team to solve this problem.

1.  check the appearance

Item	Noise motor appearance
picture
Remarks
Summery	The customer complaint motor is a patch over motor, and there is solder at the motor casing and terminals. The passenger motor terminal is seriously lifted.

2. Unqualified motor performance confirmation

NO	Customer feedback	Rated current	Speed	Resistance	Hear by ear	Judge
		≤85mA	15000±2500 rpm	30Ω±6	OK/NG
1#	With noise	75	13321	30.4	noise	NG
2#	With noise	75	13100	31.2	noise	NG
3#	With noise	77	14436	30.5	OK	OK
Picture
Remarks	1, the customer returned 2pcs single motor has obvious noise. 2. The motor connected to the board has no abnormal sound.
summery	Confirm the passenger return motor and determine that the 2pcs single motor has noise.

3. Disassemble 1pc unqualified motor and analysis noise causes:

End cap assembly	Rotator assembly	Stator assembly
NG	NG	NG
Summary: Disassemble the unqualified motor, the rosin inside the motor enters, and the other no obvious abnormalities.
Due to the limited internal space of the motor, the rosin entering the inside of the motor interferes with the motor during the operation of the motor, resulting in poor motor noise.

Remarks: 

1.The motor end cover and the casing are fixed by riveting, so the inside of the motor is not completely sealed.

2. This motor is a conventional motor,our internal patch simulation and in other customers have never appeared rosin into the motor inside, customer need check the motor patch temperature and other related conditions.