Q: How about the noise level of your motor and do you have quiet motors?
A: Normally we define the noise level (dB) based on the back ground noise and measure distance. There are two kind noises: mechanical noise and electrical noise. For the former, it's related to the speed and motor parts. For the latter, it's mainly related to the sparks caused by the friction between the brushes and commutator. There is no quiet motor (without any noise) and only difference is the dB value.
Q: Is there a detailed lifetime for your motors?
A: A: I am afraid not. The lifetime varies a lot for different models, materials and the operating conditions like temp., humidity, duty cycle, input power, and how the motor or gear motor is coupled to the load etc. And the lifetime we normally mentioned is the time when the motor rotate without any stop and the current, speed and torque change is within +/-30% of the initial value. If you can specify the detailed requirements and working condition, we'll make our evaluation to see which one will be suitable to meet your needs.