Whether you work in a paper mill, power plant, or the makers of your favorite beverage, all have something in common. They have a series of pipes that move process fluids in specific amounts, at specific rates, to accomplish a goal.
What moves those process fluids?
What makes those pumps run?
The bottom line is some facilities have a dozen motors and some have hundreds or even thousands. Making sure these motors are healthy and operational directly influences the bottom line.
Different methods of testing are available based on the criticality of your equipment.
A small combustion turbine power plant may have around 130 motors. Twenty may be small enough to replace as needed with a spare. Eighty-five are critical enough to warrant quarterly vibration testing, and twenty-five should receive full PdMA testing.
Let’s be honest.
Most facilities are aware of the importance of motors and have implemented some form of planned maintenance. Often this involves walking out with an ohmmeter or megger, checking the insulation, and saying that it looks fine.
We can equate this to a general checkup at the doctor’s office to check vitals like weight, blood pressure, temperature, pulse, reflexes, heartbeat, breathing etc. This is good enough for a snapshot in time but does not help predict future health. So once a year the doctor orders a full blood panel test to identify your risk of developing a disease, thereby enabling either prevention or early treatment.
Why do it differently?
PdMA takes a few minutes to run the test but gives a multifaceted report of motor: insulation, polarization index, inductance, resistive imbalance, capacitance, air gap, alignment, phase imbalance—each can point to a different issue within the motor.
While typical testing using the megger and ohmmeter may be sufficient for testing a throwaway motor to confirm it is functioning, this approach falls short in determining if it is functioning correctly.
Testing a 1000 HP motor needs deeper diagnostics. Plain and simple. However, it is important to also account for criticality. A much smaller motor could certainly bring down a system.
PdMA testing can be done in the field at the motor itself or at the Motor Control Center (MCC Room). Testing from the MCC room provides the ability to check the power wiring to the motor point to point, rather than at the motor. There is the potential of failure in motor leads leaving the control room—and we HAVE found that. The result is a good health check of the whole circuit. This testing will be offline typically, but there is the capability to use an online testing unit.
How do you get started?
There is a trend of younger technicians joining the workforce to replace more seasoned employees approaching retirement. There is a good chance these incoming technicians are not aware of newer technology. Traditional education does great to focus on the system, and pieces of that system, but is certainly guilty of overlooking the reliability programs needed to keep equipment in optimal health.