Compressor turning problem
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This post was finally edited by yxmqh on 2010-6-20 14:56. I would like to ask a question about the turning problem of motor drive + centrifugal compressor. I would like to ask why it is so difficult to turn a car and one person cannot do it at all. What I want to ask you is whether you should run the oil circuit first when turning on the spare compressor. Because during normal operation, there is lubricating oil between the radial bearing and the shaft of the compressor, which is the oil wedge theory. Make sure the lubricant supports the rotor. Is it true that the reason why the spare compressor cannot crank up is that there is no starting oil line, and the main shaft and the radial bearing have dry friction and the crank cannot crank up. Please feel free to enlighten me all heroes. This post was last edited by daqing01 on 2009-3-10 19:03 ]
At that time, the oil pump must be started for oil circulation, otherwise the consequences will be disastrous.
If the backup compressor here is shut down, the auxiliary oil pump will generally not stop. I suggest that if the compressor is on backup, the auxiliary oil pump should be turned on. Don't bring yourself so much trouble just to save a little electricity. Big companies are not short of money: lol
Our two compressors are turned on every day without oil delivery. Is this wrong?
In fact, it is not necessarily true. For example, for gas blowers, it is generally not necessary to start the oil pump when cranking the backup blower. Of course, it is also possible if the oil pump is started for lubrication first and then cranked. It depends on the specific regulations of the mechanical professional. If you must start the oil pump first and then turn the car, you must abide by the regulations.
The lubricating oil pump of the standby compressor must be in operation to ensure the normal operation of the oil circuit and the lubrication of the bearings (but it cannot support the rotor, which is held up by the oil film formed during operation). Prevent bearing bush from oxidation and rust. Since it is called a standby machine, it must reach a standby state to ensure that it can enter the operating state at any time in the event of an accident. If the standby machine is not running for a long time, the rotor and the bearing bush are in direct contact, and there will still be rust. There will be jamming when turning the car, which is very tight. You can find a maintenance unit, and it will be better to do a few laps hard and fast.
The unit has a normally operating oil pump and cranking oil pump. Purpose of cranking: before starting, 1. Straighten the rotor; 2. Prevent steam from leaking into the turbine from the main steam valve, resulting in thermal deformation caused by uneven temperature rise in the upper and lower parts of the cylinder; 3. Send shaft seal steam in advance; 4. Make the bearing shell oil-filled; 5. Impulse the rotor to reduce inertial force; 6. Determine whether there is a mechanical failure. The purpose of cranking after parking is to prevent the temperature difference between the upper and lower cylinders from causing shaft bending. Steam turbines with cranking devices can be started at any time without being restricted by shutdown. Otherwise, if the shaft bending is large within 12 hours of shutdown, startup is not allowed. It’s done by hand, please encourage me! Thank you!
Before cranking a motor-driven compressor, start the oil pump first, then start the oil tank heater, raise the oil temperature to the allowable operating temperature of the compressor, and then start the electric crank or manual crank for cranking. Generally, the compressor rotor can be turned 180 degrees.
If the bearing of the compressor is a sliding bearing, the oil station must be started when cranking, otherwise, the shaft and the bearing will directly rub, which will damage the bearing and the shaft over time.
1 For a motor + centrifugal compressor unit that cannot be turned by one person, it must be a relatively large unit with a power of several thousand KW and is generally equipped with an electric turning machine. 2. For a unit equipped with a complete control system, electric cranking must be interlocked with the lubricating oil system, that is, the normal operation of the lubricating oil system is a necessary condition for cranking. 3. If manual cranking is used, due to the weight of the compressor rotor and the direct contact between the shaft and the bearing when static, no oil film is established. At this time, hard cranking will cause relative friction between the metal and have a negative impact on the bearing. 4 In the answers given by some friends, they also have experiences of cranking without lubrication. In fact, it is not damaged after one disk operation, but the damage accumulates. It is recommended to perform cranking according to the requirements. 5 If the cranking does not move, you can slightly increase the torque and compare it with the historical situation of the unit. If there is an obvious abnormality, it is not recommended to increase the torque indefinitely, and the reason must be found out. 6. In the low-speed cranking state, the possibility of establishing an oil wedge is relatively small.
study* Yes, thank you all for your answers.