Pentair using less efficient motors?

[LA2240]

I recently replaced a Pentair WhisperFlo 1.5hp WFE-6 (Model 011514) single speed, circa 2000, with a Pentair WhisperFlo 1.5/0.19hp WFDS-6 (Model 011512) two speed.

One very noticeable difference between the two pumps is how much hotter the WFDS-6 motor runs. Higher case temperature (touching the outside of the case) as well as the noticeably warmer fan exhaust temperature. I haven't used a temperature gun on it, but subjectively it is a hotter motor.

Heat loss is a form of inefficiency. I notice the older motor was marked AO Smith "E-Plus" whereas the new motor is an AO Smith but without the "E-Plus" designator.

Any ideas on why a newer motor (running on the same circuit) runs so much warmer? I checked voltage at the motor and it is a healthy 240V +/-.

 

[JasonLion]

Two speed motors are not generally available with the modern high efficiency design used in the E-Plus series. Running on low speed far more than makes up for it, but when used on high speed they are about 10% less efficient.

 

[Durk]

Two speed motors are not generally available with the modern high efficiency design used in the E-Plus series. Running on low speed far more than makes up for it, but when used on high speed they are about 10% less efficient.

I would say the motors are available but Pentair chooses not to make them available on its pumps from the factory. See page six of the brochure below for e-plus Centurion two-speeds that fit perfectly on WhisperFlo's. I just upgraded my 9 year old 1.0 HP WhisperFlo with the AO Smith B2982 1HP/0.13 high efficiency two-speed e-plus New Centurion motor. This motor is high-efficiency on both high and low-speeds. I paid $269 including shipping last March.

http://www.centuryelectricmotor.com/WorkArea/DownloadAsset.aspx?id=363

Featuring an energy efficient Permanent Split Capacitor (PSC) high-speed and an
energy efficient Capacitor Start/Capacitor Run (CSCR) low speed, the E-Plus New Centurion offers
increased energy savings of up to 20% over regular two-speed motors and up to 58% over regular single speed motors.

The B2983 would work for the OP. But I don't think Pentair puts them on new pumps.