We had an enquiry from a customer with a motor mounted in a harsh outdoor area – oil field type conditions, with wash-down, dust, and occasional caustic chemical exposure. They needed an encoder fitted to the non-drive end of the motor, and asked us to recommend something that wouldn’t need constant maintenance.
This looks simple, but a shaft-mount encoder on the non-drive end of a motor is exposed to whatever the motor itself is exposed to – wash-down spray, dust, vibration from the driven load, and in this case, caustic chemicals. A standard encoder housing and seal won’t hold up long in that environment.
In actual application, the Hengstler HSD25 is a compact hub-shaft optical encoder built for exactly this kind of harsh-duty application. It’s designed for simple installation directly on a motor or machine shaft (commonly the non-drive end), with a hollow bore from 6mm up to 3/4″ (19.05mm) and a choice of two tether options. It’s rated IP67, and is also available in stainless steel to meet NEMA 4X and 6P requirements for wash-down and caustic chemical environments. The encoder uses an advanced Opto-ASIC design that’s independently validated to 400G shock and 20G vibration, so it holds up well even with rough motor vibration. Resolution goes up to 20,000 PPR, operating temperature is -40°C to +100°C, and supply voltage is 5-26VDC with a choice of Open Collector, Open Collector with Pull-Up, Push-Pull, or DLD 7272 output.
From our experience, before we quote this, we would normally check the exact bore size, housing material (aluminum, nickel-finish, or stainless steel depending on the chemical exposure), resolution (PPR), and output type needed. Hope this helps.
