The pump driver shall overload beyond its rating (including any service factor allowance) when delivering the necessary brake horsepower.

The pump driver shall overload beyond its rating (including any service factor allowance) when delivering the necessary brake horsepower.

• A. False
• B. True
• C. Not Specified
• D. Cannot Determine

Answer: (A)

Understanding motor service factor and rated horsepower shows why you don’t overload a pump driver beyond its rating. The brake horsepower the pump needs is the actual load the driver must deliver at the shaft. The motor’s nameplate horsepower is the continuous rating, and the service factor provides some extra headroom for short-term overloads. You must size the driver so the required brake horsepower is within that available headroom (rated horsepower times service factor). If the necessary BHP would exceed that limit, a larger motor or different drive is needed. For example, a 100 HP motor with a service factor of 1.15 can deliver up to 115 HP for a limited time; if the pump needs more than that, you shouldn’t rely on exceeding the rating.

Understanding motor service factor and rated horsepower shows why you don’t overload a pump driver beyond its rating. The brake horsepower the pump needs is the actual load the driver must deliver at the shaft. The motor’s nameplate horsepower is the continuous rating, and the service factor provides some extra headroom for short-term overloads. You must size the driver so the required brake horsepower is within that available headroom (rated horsepower times service factor). If the necessary BHP would exceed that limit, a larger motor or different drive is needed. For example, a 100 HP motor with a service factor of 1.15 can deliver up to 115 HP for a limited time; if the pump needs more than that, you shouldn’t rely on exceeding the rating.