ABSTRACT AFTER MASTER'S WORK THEME
(limited version)
Faculty: Electrotechnical
Speciality: Electrical systems and networks
Theme of master's work: Induction motors diagnosis
DESIGNATION OF THE NEW INDUCTION MOTOR DIAGNOSTIC METHOD
Leader of work: proff.ass. Dmitry Polkovnichenko
Email: alexm206@rambler.ru
|
|
Introduction. The asynchronous machine has received wide application in many branches of the national economy, owing to manufacture and operation simplicity. It proves to be true that the asynchronous machine consumes about 40 % of the electric power made in the world. However AM interferes with optimum use of asynchronous electric motors their high damageability (20-25 % from total of the established electric motors are annually damaged). It leads to infringement of technological processes continuity with the subsequent spoilage of production, expenses for restoration and electric motors repair, and also for restoration of normal technological processes manufacture.
Process of control automation by technological processes by use of electric motors diagnosis technical condition in hot conditions allows to lower to the minimum damage from these consequences due to early detection of arising defects.
Theme urgency. The basic kind of the machine of working mechanisms of industrial objects, owing to simplicity of manufacture and operation, are the AM with SCR. The breadth of application the AM with SCR proves to be true that such machines consume about 40 % of the electric power made in the world. Damage of engines of own needs (o.n.) power stations can lead to the block stop and that to affect stability of the electric power system work.
Use of methods and means of the control and the analysis of the current technical condition also allows to introduce technology of service of electric motors « on the condition », that is a source of essential increase of competitiveness, profitability and profitableness of the enterprise. It is promoted by rapid development of microprocessor and computer engineering.
The essence of technology of service «on the condition» consists that service and repair are carried out depending on the real current technical condition of the electric motor controllable while in service without any dismantling and audits on the basis of the control and the analysis of corresponding parameters. Thus expenses for maintenance service of electric motors decrease on 50-75 % in comparison with service « under the rules » (system of scheduled preventive maintenance).
Full diagnosis of object is necessary for introduction of technology of service « on the condition », and it is desirable to reveal all defects which influence the resource, long before refusal to be prepared for repair.
Thus, the problem of development and perfection of methods and means of diagnosis of a technical condition of electric motors on the basis of the control of parameters of hot conditions is actual.
The purpose and research problems. The purpose of work is the method development of technical diagnosis of the AM with SCR, allowing to reveal arising defects at the early stage of their development in hot conditions.
Research problems according to the purpose of work consist of the following:
- To analyse change of parameters of hot conditions the AM with SCR at occurrence of various kinds of defects.
- To develop the technical diagnosis method the AM with SCR, allowing to reveal arising defects at the early stage of their development in hot conditions.
- To estimate economic efficiency at introduction of the developed method of technical diagnosis the AM with SCR.
Planned practical result. It is planned to check up the developed method of diagnosis the AM with SCR on physical (laboratory) model for the estimation of reliability of the method and check of the measurement accuracy of diagnostic parameters.
Existing methods and means of technical diagnosis of electric motors.
Now in the world there is no uniform concept of diagnosis, exist and separate techniques are successfully applied. Basically they are carried out on the basis of the analysis of indications of instrumentations at periodic detours and by results of tests at carrying out scheduled and unscheduled repairs of the electric equipment, in particular electric motors. Rather greater terms between tests do not allow to reveal damage at the early stage of their occurrence, i.e. cannot be fixed in due time.
The comparative analysis of various methods of service of the equipment rotor type [25], has shown, that at service « under the rules » (system of scheduled preventive maintenance and tests):
- Not less than 50 % serving it is carried out without it's actual necessity;
- For the majority of machines thus frequency of their output out of operation does not decrease, moreover, reliability of work after service with disassembly and replacement of details, often decreases;
- The replacement of units is not proved by the actual condition and details with the big residual resource;
- About 70 % of defects it is caused by manufacture of works on service.
At service « on the condition »:
- The enterprise has objective data about the current technical equipment status;
- Normal work of the mechanism because of not proved intervention of the person is not broken;
- Necessary terms and volumes repair and adjusting operations are technically authentically defined, quality of their performance is supervised.
The given technology at due its organization doesn't only reduce a running cost, but also radically changes system of service of the equipment at the enterprise that allows:
- To supervise the real current technical condition of mechanisms;
- To supervise quality of manufacturing, adjustment and installation at commissioning;
- To supervise quality executed repair and adjusting operations works;
- Technically soundly to plan terms, and the contents repair and adjusting operations;
- To plan terms of purchase of spare parts in process of their necessity;
- To reduce requirement for spare parts, materials and their stocks in a warehouse;
- To raise increase the resource and reliability of the equipment;
- To prolong an interrepair time and service life;
- To get rid of "sudden" breakages of mechanisms and stops of manufacture;
- To increase the general common culture of manufacture and qualification of the personnel.
Technical means used at it, as a rule, allow not only to supervise a condition of mechanisms, but also provide the decision of problems on operative adjustment while in service and repair.
The essence of technology consists that service and repair are made depending on the real current technical condition of the mechanism controllable while in service without any dismantling and audits on the basis of the control and the analysis of corresponding parameters.
It is obvious, that to increase of the resource and reliability of the equipment, reduction of expenses connected with repair and idle times, it is necessary to pass from regulated on time preventive and repair work-regenerative to service « on the condition ».
Exact enough system of diagnosis of the current technical device status is necessary for the given transition.
|