Richard Pekelney, a member of San Francisco’s Maritime National Park Association, has used many Bender products over the years. Most recently, Mr. Pekelney had a need for a product that could monitor and identify electrical issues on the USS Pampanito, a Balao-class submarine that has been preserved by the association. Bender was delighted to assist by donating several Insulation Monitoring Devices from the ISOMETER® Series, which are specifically designed for marine and naval applications. The Bender iso685W-D-P was the perfect fit for the USS Pampanito as these devices can monitor, annunciate and locate insulation failure. The iso685W-D-P is intended for highly-corrosive environments and can withstand high levels of humidity, vibration, and other environmental conditions found on naval applications.
Bender Insulation Monitor Devices (IMD) were installed on the ship's ungrounded 250 VDC Auxiliary System and 115 VDC Lighting Circuits. The devices showed a 180 kΩ insulation reading, this closely matched Megger readings with rectifiers and monitors disconnected. After they isolated the faulty lighting circuits, the insulation resistance value increased to 680 kΩ.
A second Bender IMD was installed on the ungrounded output of a 75 kVA transformer that supplies the boat's historic AC Motor Generator set circuits to the modern 40 kVA DC rectifier. It read 440 kΩ when installed.
A third Bender IMD was added to the ungrounded 250 VDC emergency lighting circuit. An isolation transformer was installed to restore an ungrounded (IT) source for the emergency lighting circuit. The IMD read 680 kΩ when installed. Additionally, the emergency lighting controller was simplified by removing an unused test button timer, DC/AC relay, indicator lights and associated circuitry.