Re: Pumps for Boiler Circulation
Posted by:
peter heid (IP Logged)
Date: January 09, 2005 01:03PM
<HTML>Andy,
These pumps use a metal can around the stator on the dry version and the stator is immersed on the wet type. You will lose some electrical power through induction if there is a can around the stator but this is converted to heat which is practically all absorbed into the water. It is the same with any power converted to heat by the normal motor operation and any leakage in the seal area automatically goes into the feed water, nothing is lost or wasted. The thermal response of the motor is limited by the water temperature and the increase in restistance in the windings is also limited, preventing thermal runaway and the large increase in power consumption seen at elevated temperatures of operation. In a perminate magnet motor you have to energize the stator, just the same as a poly phase induction motor. The permanate magnet motor would be fine in this application and it could be run with a wet or dry stator also. A typical pump motor has a estimated life span of 100,000 hours while a comon DC motor is typically 11,000 hours. With no heat build up, cooled continous fluid for bearing lubrication and no seals to leak, boiler circulation pumps of this varity are by far the most reliable and efficient available when all factors are combined over the service life of the unit.
Dick,
A permanate magnet will lose power as it approches it's critical
temperature and most should be kept under 350 degrees F..
George,
Yes, there is nothing suitable for the size of boiler used in a auto but this type of pump can be built from existing motors. My purpose here was just to point out how the most modern steam systems have gained a bit of a percent in efficiency while reliability has gone up, and maybe a little bit of the info will help the experimenter.
Peter Heid</HTML>