COVER STORY
10
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March - April 2015
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www.machinerylubrication.com
Cold engine startups at very low temperatures have
been a problem for consumers, manufacturers of power
systems and the petroleum industry. With a cold start,
the flow of circulating oil (a dielectric liquid) in the system can
induce voltage spikes in portions of the circulation manifold during
the initial warm-up period. When exposed to this spike, sensitive
components such as sensors and microprocessors may break
down and ultimately shut down the engine if the component is
critical to operation.
When a power system is cold, its circulating oil has a very high
viscosity and very low electrical conductivity. The oil will warm as
the engine heats up, but for a period after a cold start, there will be
the danger of static electric buildup in the oil and of potentially
damaging spontaneous discharge.
Flow electrification of liquids has been a source of numerous
industrial hazards, primarily in the petroleum and power indus-
tries. This effect occurs in improperly grounded systems carrying
fuels, lubricating oils and other hydrocarbon liquids. This is why
some commercial gasoline fuel hoses in the United States have an
attached ground wire to dissipate electric charge accumulation
