Page 75 of Contactors and Motor Protection by Moeller Electric USA

thermal overload relays reliable consistent motor protection thermal overload motor protection has come a long way from the eutectic alloy solder-pots and replaceable heaters of yesterday today s iec-style relays from moeller feature bimetal technology that is very consistent reliable and economical r a great combination most of our thermal relays are specifically designed to be close-coupled to a matching contactor all ze zb and z5-series overloads which cover the range from fractional to 250a are direct mount designs the resulting motor starters fit in an extremely compact footprint as narrow as 45mm protection for larger amp sizes is accomplished with moeller s zw7 overload relay with integrated current transformers superior iec designs class 10 protection for modern motors many standard features z-series overloads are the ideal choice in most industrial starting applications below 250a all relays are class 10 which means they trip within 10 seconds of a locked rotor condition many motor manufacturers agree that class 10 devices offer superior protection against overloads and also extend motor life by protecting winding insulation all of moeller s thermal overload relays have ambient temperature compensation automatic or manual reset and a test button in addition trip indication and a tripfree release are important safety features trip-free releases prevent the device from being held closed even in the event of an overload ambient temperature compensation test off button automatic manual reset trip indication trip-free release integrated no nc contact easy installation and operation once the overload is installed a convenient dial adjustment is used to set the motor full load amps moeller s factory calibration assures that your motor investment is protected accurately 76

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