Encoders…The Weakest Link

Repairs for Damaged Encoders

Talk about out of proportion!   It struck me today as ironic that an entire manufacturing plant’s production can literally be held hostage by the failure of one relatively inexpensive part:  an encoder.

When motion control is important to your production, then your encoder is a key component… and yet, often the weakest link.  Encoders are repeatedly exposed to shock, dirt, vibration,  and high temperatures that test their toughness.

If you can afford it, make sure you buy the latest and greatest encoders.   These have built-in diagnostics systems that monitor the device’s functioning and lets you know when maintenance is needed before it becomes a production disaster.

Wireless encoders, Quadrature to USB, High Resolution Linear Encoders, and the newest Absolute Encoders are making all kinds of headway into the future of motion control so do some research on what will work best for your application before you plunk down your money.

That said, there’s a lot of rotary encoders out there doing their job 24/7.  If yours seems to be headed for the title of “Weakest Link” here’s a handy list of what might be going wrong with your encoder:

  • Worn-out Ball Bearings

How to tell:  Entire drive unit becomes irregular as the frequency inverter tries to compensate for the loss of several pulses.  This is usually due to poor installation of the bearings resulting in premature wear.

  • Loose Contact

How to tell:  You get random faults.

  • Dirt/Dust Particles

How to tell:  The encoder produces one pulse too few.  Why?  Dust particles on the incremental disc fools the rotary encoder into detecting two increment lines as just one.  Use an encoder with an external plug connection to help avoid this.

  • Moisture

How to tell:  Sporadic failures.  Moisture may have gotten in through the cable gland.

  • Overheating

How to tell:  Usually total failure.  Hot exhaust air from the motor fan passes over the encoder causing it to overheat.

The good news is that many encoder problems are economically repairable.  ACS Industrial’s dedicated encoder repair tech team has all the manufacturers covered including BEI encoders, Heidenhain encoders, Dynapar, Allen Bradley, Fanuc, Sumtak, Tamagawa, Yaskawa, Fincor, and many others.