HOME INTERNATIONAL SALES / SERVICE PRODUCTS CONTACT MORE DC CONTACTORS - FAQS What Does "LVD" mean? Low Voltage Disconnect What is the maximum switched main contact voltage? 60VDC without Magnetic Blowouts/otherwise 96VDC. Type SW190B has double pole switching and can handle 120VDC What are the main contact materials? Presently about 10% Cadmium, the balance is Silver. What are Magnetic Blowouts? Rare Earth Magnets molded into the top cover which produce magnetic fields which act on the main contact arcing, thereby extinguishing the arc outwards. This is particularly true in the case of "Inductive Loads". What is the Mechanical Life Expectancy of a contactor? Based on a Mechanical Switching Formula located under the specifications section. Generally speaking, Mechanical Life of the contactor is based on type of load being switched along with the frequency of main contact switching-(duty cycle). For Severe Load Switching applications, the expected MTBF is between 1-1.5 million cycles. For Infrequent Light Load Switching-between 2.5-3 million operations.) What is the worst type of load to switch? Inductive Loads First, Capacitive Loads Second, Resistive Loads are the most forgiving loads to switch. What is "HOT" versus "COLD" switching Hot switching means closing the main contacts directly on the load, versus Cold switching means first closing the main contacts before switching the load.-The worst load switching is "HOT" switching of Inductive type loads). What are ways in which to lower the power consumed by the operating coil? Magnetic Latching/Coil Chopping, which are options for Albright DC Contactors) What types of coil configurations do you have? "CW"= Continuous Wound, rated for 100% Duty Cycle, "Intermittently Wound"= 60% Duty Cycle, "Prolonged Wound"= 80% Duty Cycle. Continously wound contactors are identified by CO written on the label In a Static Power System, why do we need to size the coil voltage above the nominal rating, i.e. 24VDC/48VDC? In a normal Static Power System, we need to take into account the "maximum battery equalization charge voltage" whereby if the nominal system DC voltage is at 24VDC, the maximum coil voltage will be around 30VDC CO. If the system nominal voltage is at 48VDC then we would size the maximum coil voltage at 60VDC CO. The reason for this is to alleviate any potential for premature coil thermal runaway. What type of mounting brackets do you have? The three types of mounting brackets are listed on Pages 2-3 of the Albright Technical Data Sheet. What is the maximum current rating of the Albright DC contactor product line? The maximum current rating is: 1800 amps, which is the SW1500 series. Are Albright DC contactors UL rated? Yes, there are two separate UL ratings for different applications, EV/MH-UL certification based on the UL583 Industrial Truck Standard, versus the UL Rating for Static Power Systems-UL1778, and most recently UL1801. What is the coil ratings range for Albright DC contactors? From 6VDC to 300 VDC in the standard Albright product line, i.e. SW80 through SW1500 series. In the Albright DC contactor range miniature series the coils may be wound from 6VDC to 120VDC. Are spare parts available for the Albright DC contactors? Yes, a separate Albright Spare Parts List is available. What is the "end part number" on each Albright DC contactor label called? This "suffix" number is called a "precise identity number" which identifies that specific Albright DC contactor number with a specific customer and contactor special features. How can you tell if a contactor has magnetic blow outs? This letter B in the model number such as SW180B indicates the presence of blow out magnets. In case of contactor SW200 however, the type SW200 means with blow outs and SW200A means without blow outs. Are the main contacts polarity sensitive? The contactors without blow out magnets can have any polarity on the main contacts. Types with blow out magnets need to be wired up with the higher potential at the terminal marked with a + sign on the top cover. This is necessary to ensure that the blow out magnets push the arc out of the contactor. Curtis International Sites: