Electric Motors
Motor Service Factor Calculator
Enter values for Motor Service Factor that describe the same case, then use permitted service-factor load as a check rather than a design approval.
Motor Service Factor inputs
Use measured values for Motor Service Factor when available and rated values only when they describe the same condition.
Keeping service factor tied to the case
Each Motor Service Factor entry should describe the same circuit, device, billing period, or test condition. Mixed sources can make a plausible but wrong result.
Rated horsepower is shown as 20 hp. Enter rated horsepower in hp.
Service factor is shown as 1.15. Enter service factor.
Field context for Motor Service Factor
Motor Service Factor should distinguish starting, running, and overloaded motor conditions. A nameplate value is not always the same as a measured load value.
For Motor Service Factor, a useful note is the reason the calculation was run: troubleshooting, sizing, comparison, billing review, or a quick unit check.
How permitted service-factor load is calculated
The Permitted service-factor load value and any supporting metrics belong to this same Motor Service Factor case, not to a nearby run with different inputs.
Read the Motor Service Factor equation from the units on this page. A familiar symbol can shift meaning between DC, AC, energy, component, or billing work.
Where Motor Service Factor can break down
Continuous use of service-factor capacity can shorten life.
Records for service factor
Record the motor nameplate, supply voltage, enclosure, duty, and whether Motor Service Factor describes running or starting.
If a later Motor Service Factor run changes only service factor, label it as sensitivity work. Several changed conditions deserve a new baseline.
Before saving permitted service-factor load
How should multiple scenarios be compared?
For Motor Service Factor, keep the baseline unchanged, duplicate the case, and adjust one uncertain value at a time so the reason for the difference stays visible.
What does a Check inputs message usually mean?
On Motor Service Factor, Check inputs usually means a required entry is missing, outside its allowed range, or creating an undefined operation.
What should be recorded with the answer?
Save the Motor Service Factor inputs, unit basis, operating case, and result note so permitted service-factor load can be reproduced later.
Can the default values be used as a recommendation?
No. The Motor Service Factor defaults only demonstrate the form. Replace them with measured or rated values for the actual electric motors case.
What not to assume from Motor Service Factor
A simple result is easiest to misuse when the input source is not written down. Label service factor as measured, rated, assumed, or calculated before the answer leaves this page.
Nameplate values and measured load values can both be valid, but they should not be blended without a note.