BRUEL & KJAER System V Instruction Manual page 7

spension arrangement which provides isolation at most frequencies and has the facility of
full 360 0 positioning . The 4801 S is a simplified base upon which the Exciter is fixed in
one position . Uniess otherwise stated, in this book the 4801 T is the Body referred to.
For same applications, it could be preferable to use a Permanent Magnet Exciter Body
4805. It has the advantage of quieter operation since it can be operated without cooling,
but the disadvantage of reduced force rating . Use of the permanent magnet bodies re­
duces the power available to 70% of that available with the 4801.
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