It has been an good couple of weeks here at Unit 3 Compliance with some very interesting products to work on.
Firstly, I received confirmation from a previous customer that their product has passed the required EMC certification testing at their accredited laboratory with the modifications that we incorporated during our problem resolution work. This is excellent news for all concerned!
Then things started off with some radiated emissions EMC testing and fault finding on quite a complex and clever piece of medical laboratory equipment with multiple interconnected boards, display, motors and servos. A few problems were identified and feedback given to the customer about potential improvements.
Noisy DC motors were again the theme in some more radiated emissions testing, requiring additional suppression on the motor terminals, made all the more challenging by the tight mechanical constraints of the product. Differential mode suppression on the terminals using ferrite beads to reduce the brush noise is the most effective solution but without a well defined RF return path to the brushes any noise reduction will ultimately be a compromise. More testing is being performed with some small filter PCBs mounted right on the motor terminals.
Lastly, our screened room test facility is almost completed and is being used for some mains and DC port conducted emissions testing with buck converter switching noise providing a challenge.
“Problems worthy of attack prove their worth by fighting back!”
Radiated emissions fault finding and pre-compliance in the Unit 3 Compliance fully anechoic chamber