Types of Machines
Machines are categorized into three major groups. They are high speed machines, low speed machines and impact machines.
Low speed machines – Compressors and reciprocating engines come under this category. They produce unbalanced forces. The speed of such machines is usually smaller than 600 rpm.
High speed machines – Turbo rotary compressors fall in this category of machines. These machines may have speeds ranging from 3000 to 10000 rpm.
Impact type of machine – These machines produces impact loadings. Forge hammers fall in this machine category. The operating speed is usually 60 to 150 blows per minute.
Types of Machine Foundation
The type of foundation for a machine depends on the type of machines. Usually three types of foundation are provided. They are block foundation, box or caisson foundation and wall type foundation. These foundations are respectively shown in Fig.1 (a), (b) and (c).
Block foundation – A block foundation consists of a pedestal resting on a footing. If more than one machine of similar nature is to be installed in a workshop, they can be profitably mounted on one continuous mat. A block foundation has a large mass and smaller natural frequency. Usually block foundation is provided for compressors and reciprocating engines.
Box or caisson foundation – If a lighter foundation is to be provided, this type of foundation is used. In this type weight of foundation is reduced and its natural frequency is increased.
Wall type foundation – This type of foundation consists of a system of wall-columns and beam-slabs. Each element of such a foundation is relatively flexible. Steam turbines are provided with wall type of foundations.