A documented diagnostic program for DC gearless machines that replaces guesswork with recorded data, before a modernization, after a symptom, or any time the machine’s condition needs to be known rather than assumed.
The most expensive sentence in elevator modernization planning is “the machine is probably fine.” The second most expensive is “the machine probably needs to go.” Both are guesses, and buildings spend real money on guesses every year: modernizations scoped around machines nobody actually tested, and healthy machines replaced because nobody could prove they were healthy.
MATH, EMR’s Motor Analysis Testing and Health program, exists to end that guesswork. It is a comprehensive, instrumented evaluation of a DC gearless machine’s condition, performed in the machine room, that produces a detailed written report with recorded values and clear recommendations. Consultants use it to scope modernizations accurately. Building owners use it to make capital decisions with evidence. Contractors use it to diagnose machines that are misbehaving and to document condition before and after work
What the MATH Evaluation Includes
The program combines observation under load with disconnected electrical testing, because each reveals what the other cannot.
The machine under power. We begin with detailed observation of the motor as it operates, recording how it performs and measuring voltage and amperes on the fields and armature during up and down runs. A machine’s behavior under real load exposes conditions that static testing misses.
The machine opened up. With the motor disconnected from the controller, we inspect the brush assembly, brush faces, wiring condition, insulation, isolators, air gap, and the oil and carbon contamination that tells the story of how the machine has been maintained.
Instrumented electrical testing. Using an electronic Megohmmeter, we check resistance to ground on the field coils, interpoles, armature, brake coils, and brush assembly. The field coils are then drop tested at 120 VAC, with the ohm values and inductance of each coil measured and compared, which reveals shorted turns that a simple resistance check can miss.
Bar to bar commutator testing. Finally, we perform a bar to bar test on the commutator, measuring inductance and impedance throughout the armature. This is the fine grained test that locates developing winding problems at the level of individual bars, long before they announce themselves in service.
The deliverable. The customer receives a detailed report compiled from every recorded result, with our recommendations. Not a verbal impression. A document that a consultant can put in a modernization specification, an owner can put in a capital plan, and a contractor can put in a job file.
Where MATH Earns Its Keep
Before modernization. This is the program’s original purpose. MATH evaluates the condition of DC gearless machines before modernization begins, and the results help the consultant, building owner, and elevator contractor plan their course of action. A machine that tests strong can be retained and integrated, saving the project real money. A machine that tests weak gets replaced on the project’s schedule instead of failing on its own. Either way, the decision is made on data, a discipline consistent with the modernization planning resources published by industry bodies such as NEII, the National Elevator Industry Inc., and one we also walk through in our guide to weighing MG set repair against modernization.
When something is wrong. MATH also serves as general testing to identify issues occurring in a machine. Intermittent faults, unexplained performance changes, and disputes about what a machine actually needs all resolve faster with instrumented data than with competing opinions.
As a condition baseline. Recorded values from a MATH evaluation become the reference point that future testing is compared against, the same trend based philosophy behind our motor cleaning service and major maintenance overhaul, both of which include electrical testing at every visit.
And because MATH is performed by the same organization that rebuilds these machines, the recommendations in the report connect directly to solutions: shop repair and rewinding, onsite field service, the ARM program for Otis 219HT machines, or the honest answer that the machine is healthy and needs nothing at all. We test machines we will never touch again, and that is fine. The report is the product.
Planning a modernization or chasing a fault? Call (609) 392 6149 or request a MATH evaluation for your machines.
