【 Weak current College 】 the air conditioning with cooling technology law questions and answers reference--6-Power By 【 China power house network 】

251, a combined air-conditioning unit coolers, heaters should perform before installing test pressure of the hydraulic pressure test for 0.98Mpa. To confirm that no leakage. （∨）
252, central air conditioning system pressure test pressure gauge accuracy requirements for 2.5 level and above. （X）
253, and low-voltage side of filling liquid refrigerant can cause "liquid hammer", damage to the compressor, it must be absolutely avoided. （∨）
254, from high-voltage side charging refrigerant, because the internal temperature of refrigerant cylinders, so the refrigerant cylinder immersed in water of 35 ~ 40oC for filling. （∨）
255, practice of content should be scientific and reasonable, concise, easy to remember and implementation. （∨）
256, unmanned operation of the equipment room, managers do not need to regularly check the device operation. （X）
257, handing the kinds of problems found, General questions should be handled by a successor, shift after shift to finish will be able to leave. （X）
258, on new staff in accordance with the first training, induction principle, after obtaining employment qualifications before permitting independent operation. （∨）
259, compressor suction pressure = actual evaporation temperature corresponding saturation pressure + suction pipe pressure drop. （X）
260, compressors of actual exhaust pressure = condensing temperature corresponding saturation pressure + exhaust pressure drop. （∨）
261, two-stage compressor functioning exhaust temperature is 70 ~ 145oC. （X）
262, new compressor shaft seal severe oil spills in the crankcase is too much lubricant. （X）
263, freon system clouds of oil through the collection to the means of the system. （X）
264, ammonia system oil separator should weekly drop oil once, condenser should put oil per month. （∨）
265, ammonia system air emissions through the air separator, liquid can be placed at the top of the condenser air valve emissions. （∨）
266, hot gas defrosting iscompressor discharge of hot refrigerant vapour in the evaporator heat release, the evaporator surface of frost layer melt. （∨）
267, and hydraulic fluid reservoir after the deposit amount shall not exceed the volume of the reservoir and dispenser of 70%. （）
268, large and medium refrigeration system add refrigerant usually practices: liquid ammonia system shutdown plus; freon system with liquid. （X）
269, pressure gauge, thermometer, solenoid valve, control valve, safety valve, and so should periodically adhere to test, validate the General once every year. （∨）
270, equipment allows operation of non-violent and violent close all valves. （∨）
271, hot welding system leakage points should strictly observe the safety regulations for welding, the site should have a set of measures, the system should be depressurised before welding. （∨）
272, "bathtub curve" is the parts wear characteristics curve. （）
273, regular maintenance is a planned and systematic way the preventive inspection and repair. （∨）
274, as long as they adhere to good routine maintenance operations, will be able to maintain the equipment in good condition, to achieve the target. （X）
275, refrigeration system long-term outage, the low pressure side and compressor pressure should be maintained to avoid 0.02Mpa air into the system. （∨）
276, in order to save money, the compressor clearance of split pin can be used again. （X）
277, found that the heat exchanger and pressure vessels have local deformation raised, for the safe operation of the equipment, the replacement shall immediately proceed to scrap. （X）
278, oscilloscope-degree adjustable and focused regulation do not affect each other. （X）
279, oscilloscope can be used to measure the frequency AC signal. （∨）
280, DT-830 digital multimeter measurement range expansion of tributaries current is via shunt circuit. （∨）
281, to make 1 AC signal could oscillograph temperature displayed on the screen, to fine-tune the "brilliance" and "focused" knob position. （X）
282, oscilloscope y axis liquid can be scanned. （）
283, basic digital multimeter measurement circuit is a DC voltage measuring circuit 200mV. （∨）
284, digital multimeter in a liquid crystal display industry shows signal frequency for 60HZ. （X）
285, electronic leak detector's way halogen pick by inverter DC high-voltage step-up and full-wave rectifier times. （∨）
286, DT-830 digital multimeter measurement of millivolt to level voltage signal is the instrument to zoom in on the signal first after rectification. （∨）
287, voltage analog measuring multimeter stalls mistaken use of current file, causing damage to the instrument. （X）
288, clip-on ammeter in magnetic circuit is composed of forceps-like core. （∨）
289, clip-on ammeter of winding is measured currents in the jaws by wire. （∨）
290, compressor motor windings and motor, winding interruption burning, winding road, earth leakage may use multimeter ohm stalls. （X）
291, regular power can prevent moisture metamorphism in the components of the oscilloscope to maintain equipment in normal use. （∨）
292, air conditioner capillary as happened to plug a compressor of exhaust pressure rise, increasing the operating current. （X）
293, evaporator effect of surface dirt, heat, will reduce the pressure of the refrigerant, compressor operation current decline. （∨）
294, air cooled condenser surface dirt, causing adverse to refrigerant heat pressure, the compressor running-current. （∨）
295, growth in the heat pump air conditioner in the heating runs, if outdoor fan motor stall, you will reduce the absorption of heat, pressure on the high side, so no high voltage controller. （∨）
296, refrigeration systemFilter blockage, will cause the compressor discharge pressure, running-current. （X）
297, 220V, 40W bulb of lamp check motor winding insulation with the enclosure. If the filament is the human eye barely visible red, you may think the motor insulation performance, you should repair it. （∨）
298, thermostat setting small temperature difference can cause frequent starting and stopping the compressor. （∨）
299, compressor shaft seal serious leakage is due to the crankcase lubricant. （X）
300, compressor efficiency difference causes the refrigeration system evaporator pressure too high. （∨）
There are 301, condensers, cooling system and air-refrigerant shortage will cause condensation pressure too high. （X）
302, air conditioner out wind water because the air flow is too small and the evaporator surface oil oil layer. （X）
303, refrigerant charge, control electrical failure will result in refrigeration equipment continuous working non-stop. （∨）
304, piston and cylinder clearance is too large, too much lubricant residues will cause a thumping sound in the cylinder. （∨）
305, excessive engine is screw compressor discharge temperature or overheat. （X）
306, screw compressor compression ratio than the General cause body temperature is too high. （∨）
307, Mechatronics products is in a traditional mechanical products coupled with modern electrical products. （X）
308, Mechatronics and traditional automation is one of the most important difference is the intelligent system. （ⅴ）