A-A-53468 Furnace, Dental Laboratory, ElectricThis commercial item description covers an electrically operated, heating plate type, burn-out and heat treating furnace, with pyrometer, automatic temperature controls and replacement heating plates, as specified below: Type I.-complete Furnace Type II,- Replacement Heating Plates Style 1-Rear Plates Style 2- Side Plates.

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A-A-53468

(f) After the three minute heat soak period, set the desired temperature for 1500°F (816°C).

(g) When the pyrometer indicates a furnace temperature of 1200°F (649°C), begin to check for melting of the Tempil every 25°F (14°C). When checking, open the furnace door just enough to determine at a quick glance if the Tempil has begun to liquefy around the edges. Keep the furnace door closed as much as possible during this observation period to prevent heat loss.

(h) When the Tempil pellet begins to melt or liquefy around the edges, the pyrometer shall indicate 1300°F (704°C) ± 14°C). Tempil pellet has a melting point of 1300°F (704°C) ± 13°C) (±7°C).

Equilibrium temperature. The furnace shall be connected to a regulated 115 V, 60 Hz supply. The furnace shall be empty and the door closed. The temperature controller shall be set at 1700°F (926°C). Equilibrium shall be attained within 3 hours when test is performed at room temperature 68°F (20°C).

Power rating. The power consumed shall be determined by a suitable watt meter with the furnace operating at rated voltage and at the equilibrium temperature attained.

Dielectric strength test. All electrical component parts shall be tested after complete assembly an shall withstand without failure, a dielectric test of twice the rated voltage plus 1,000 volts or a total of 1,250 volts applied for one minute. This test shall be made on each of the individual lines of the circuit, using the metal frame as the other leg or ground of the 1,250 volt test.

Leakage current. The leakage current test shall be performed in accordance with UL-1262.

Contractor certification. The contractor shall certify that the product offered meets the salient characteristics of this description and conforms to the producers’ own drawings, specifications, standards, and quality assurance practices. The Government reserves the right to require proof of such conformance prior to first delivery and thereafter as may be otherwise provided for under the provisions of the contract.