PLC control two pump start-up failure solutions to problems

Situation:in the double liang steam double-effect lithium bromide absorption air-conditioning unit,the use of omron PLC (PA204S C200HE-CPU42,power supply) to control the start of two pumps. When,in turn,start the two pumps,often led to the suspension of the power of the PLC,thus stop running program.Second,the detection of 1,use the meter to measure the voltage electric motor 12v 500w waveform of two pump ordinal startup PLC power PA204S ac voltage of the power supply change found:when did not start the electrical motor 12v 1000w pump,the voltage of the power supply is normal,when start the two pumps,instantaneous fell to the power supply voltage of 184 v,184 v and the duration of the above 25 ms,PLC to stop working,and to determine the effect of pump power of PLC.2,in order to solve this problem,respectively for the following tests: A) driving the pump first,delay around 10 s to start small pump,power supply voltage drop to about 190 v,the instructions first,pump makes instantaneous voltage drops,later start small pump,affect smaller,but it need to modify the PLC program.


B) because the pump power supply is turned by high tension line through a transformer,transformer capacity,can be considered a large capacity of transformer,may make the pump will be smaller influence on the PLC power supply voltage.C) in the PLC power supply termination a large capacitance,but the effect is not obvious.D) finally in one power supply transformer converted by a 220 v power supply to PLC,found that even in the start two pumps at the same time,PLC power supply voltage drop is only about 204 v,204 v,the can.Conclusion:as a result acmotortrading.blogspot.com of the PLC power supply is supplied with water pump in the same way,and the plant's transformer capacity is small,so in the start two pumps,caused the PLC power supply voltage drops below 85% of rated voltage,and duration of more than 10 ms,resulting in PLC detected power interruption,stop working. So the advice from the transformer converted one by one in the 220 v power to separate for PLC,which can solve the problem.

How to use multimeter testing SCR

 Unidirectional and bidirectional silicon controlled rectifier thyristor SCR points two kinds,are three electrodes.One-way thyristor cathode (K) and anode (A) and control (G).Bidirectional thyristor is equivalent to two single SCR reverse in parallel.Is one of the one-way silicon anode and cathode in the other side,said the terminal T2,one of the one-way silicon cathode and anode is connected to ac induction motor the other,says the terminal T2,the rest is for control (G).1,single,bidirectional thyristor discriminant: first as A two pole,if it is,but test Pointers are not moving (R x 1 block),may be A,K or G,A unidirectional thyristor (for) can also be extremely T2 and T1 or T2,G motor run capacitor (for bidirectional thyristor).If there are instructions for a single measurement dozens to hundreds of Europe,will be as one-way thyristor.


For K and red pen receive pole,the black pen for G pole,the rest is A pole.If the positive and reverse test instructions are dozens to hundreds of Europe,will be as the bidirectional thyristor.Turn the knob to R * 1 or R * 10 survey,in which www.facebook.com/dongfeng.motor there will be a little older resistance,a red pen is larger for G pole,black pen that provides for the T1,the rest is T2.2,the difference of performance: turn the knob to R x 1 block,for 1 ~ 6 A one-way thyristor,K very red,black pen at the same time through to G,A pole,in keeping the black pen is not out of electrical motor A very great condition disconnect G,pointer should indicate dozens of Europe to euro one hundred,has triggered thyristor at this time,and low trigger voltage (small or trigger current).And then instantaneous disconnect A very connected,pointer should be returned to the up position,suggests that SCR is good.