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Metal Casting Technologies : Whos who September 2011
66 www.metals.rala.com.au Back to the Troubleshooting induction furnace melting operations General he troubleshooting procedures contained in this section list the more common faults which may occur during the use of the equipment. Probable causes and solutions are provided to expedite corrective action. Except for visual checks of the meters and lights on the outside of the furnace cabinet, all trouble shooting, maintenance, and repair must be performed by qualified maintenance personnel. These qualified maintenance personnel must be able to recognize "shock hazards" and be trained in the safety precautions required to avoid possible injury or death. WARNING: Disc connect all ele ectric cal powe er (c circu uit breakers and co ontrol po ower off) b beforre w workkingg on n the equipment. Unless speciifically ly called d for, r, do o not troubleshoo ot the eq quipm ment w with elec ctric cal power applied. Procedure ● The PT is a good nondestructive technique that can be used succeEffective trouble shooting consists of: ● The PT is a good nondestructive technique that can be used succeIdentification of a fault or problem. ● The PT is a good nondestructive technique that can be used succeIsolation of the problem to a particular area within the system. ● The PT is a good nondestructive technique that can be used succeSolution of the problem by adjustment, repair, or replacement. The procedures described in this section will generally state the nature of a problem and then refer the technician to a table(s) where detailed troubleshooting procedures are outlined to assist in effective repairs or solutions to problems. CAUTION: Do no ot disas ssemb ble pa arts u untiil ea ach component is ta agged a and prroperrlly ide entiified d. As sse emb ble all parts in reverrse orde erofd disass semb bly. Obs serv ve proper torque va alues. D Do nott change con ntroll bo oard d adjustments witthout prroper authoriza ation n. Indicators The cabinet is provided with visual indicators showing system conditions. When a malfunction occurs, check the lighted indicators and meters to isolate the fault. Normal furnace or melting operations should be in accordance with the procedures described in the Operating Procedures Section. When an abnormal condition occurs, such as low KW output, appropriate lights will show the possible fault to isolate the problem. Refer to the appropriate troubleshooting paragraph and reference table to isolate a fault and affect a solution to the problem. General familiarity with checkout, test, and start-up procedures (and drawing) will help in isolating problems and assist in troubleshooting procedures. Power failure Loss of electrical power from a utility or from the power supply requires immediate attention to prevent damage. If the power failure is a failure on the utility lines themselves, proceed immediately to the section on furnaces. Power unit failure Induction furnace units are protected from damaging internal and external electrical transients and control malfunctions by the quick-trip circuit breaker and AC interrupter. An occasional trip of the unit may be tolerated. However, a brief maintenance check of the unit should be made after any circuit breaker trip. Only if a check of the unit reveals some repairs are required, or if the circuit breaker cannot be reset, does the situation require further action. Furnace protection If the repairs appear extensive or if the nature of the malfunction is not readily apparent, then measures must be taken to protect the furnace from damage. If the furnace is empty with relatively cool lining, all that may be required to protect the lining is to place a cover on the furnace. If the furnace is empty with a hot lining, it may be necessary to provide a torch or other source of heat to protect the lining from thermal shock. The nature of the lining will determine the appropriate action. In most cases, a normal shutdown procedure can be followed. If power is lost with a molten load, the following must be considered: Safety in induction furnace operations T By Prof. John H. D. Bautista, PEE, RMetE, MBA; Technical Consultant, Phil. Metalcasting Association., Inc. --PART3--
Whos who September 2012