MDA MAY-JUNE 2019 MDA May-June 2019 | Page 58

Global Global GHM edia GHM edia B usiness MDA MDA B usiness Journal book in series Journal “This article has been excerpted from the textbook “Electro-Hydraulic Components and Systems” ISBN: 978-0-9977634-2-3 Applied Technology Center MSOE’s Applied Technology Center™ includes several centers of excellence, offering state-of-the-art resources and facilities. Hydraulics Versus Electrical Systems - CHAPTER 1 Author Dr. Medhat Khalil 1.2.6- Cleanliness of Operation 1.2.7- Maintenance of Operation The work environment of an electrically-driven machine is mostly cleaner than the work environment of a hydraulic driven machine. A hydraulically driven machine, as shown in Fig. 1.23, may experience oil contamination (1), oil leakage (2), and dirt on the surfaces of the hydraulic components (3). Agricultural machines should use biodegradable hydraulic fluids (4). Hydraulic fluids, other than the biodegradable ones, are not friendly to the environment and must be recycled (5). Possible toxicity of hydraulic fluid restricts such systems from some applications, e.g. food and pharmaceutical industries. Maintenance requirements of an electrically driven machine are much less than a hydraulically driven machine. Many of the electrical components are maintenance-free. Examples are shown in Fig. 1.24, maintenance free motors (1) and maintenance free hoists (2). Since 80 % of hydraulic system faults are due to the oil contamination, it is important to keep such systems well maintained. Additionally, hydraulic fluids are expensive and require replacement at a specific number of working hours. The figure shows a dirty oil filter (3) that must be replaced. Fig. 1.23 - Cleanliness of Hydraulic-Driven Machine Fig. 1.24 – Maintenance Requirements for Electric and Hydraulic Machines The book can be purchased online from www.compudraulic.com 58 58 | may-june | may-june 2019 2019 Global MDA MDA Journal Global Journal