54M-1BB-1AL Grayhill Inc, 54M-1BB-1AL Datasheet - Page 4

• Manufacturer Part Number: 54M-1BB-1AL
• Description: 54M30-01-1-03N & 01-1-12N-C T, Military 85&deg
• Manufacturer: Grayhill Inc

Specifications of 54M-1BB-1AL

• , 30°: , 1 Deck, 1 Pole/deck, 2 Positions/pole, Non-shorting & 1 Deck, 1 Pole/deck, 2 Positions/pole, Non-shorting, 54M-1BA-1BA
• Lead Free Status / Rohs Status: Compliant

Insulation Resistance
This is the resistance between two normally
insulated metal parts, such as a pair of terminals.
It is measured at a specific high DC potential,
usually 100 Vdc or 500 Vdc. Typical values for
new switches are in the range of thousands of
megohms. These values usually decrease
during switch life. This is a result of build-up of
surface contaminants. Typical industry standard
“end of life” criteria for the parameter are:
Another special test condition is commonly
specified. It measures insulation resistance for
switches in a high humidity atmosphere (90%-
98% R.H.). In this condition, condensation of
moisture commonly occurs on the surface of the
insulating material. Some types of insulation will
absorb varying amounts of moisture. This will
normally lower the insulation resistance. Typical
industry values for this condition are:
Dielectric Strength
This is the ability of the insulation to withstand
high voltage without breaking down. Typical
values for new switches in this test are in excess
of 1500 Vac RMS. During switch life,
contaminants and wear products deposit on the
surface of the insulation. This tends to reduce
the dielectric withstanding voltage. In testing for
this condition, a voltage considerably above
rated voltage is applied. Then, the leakage
current is measured at the end of life. Typical
industry standard test voltages and maximum
allowable leakage currents are as follows:
Voltage breakdown is another method for
describing the ability of the insulating material to
Grayhill, Inc. • 561 Hillgrove Avenue • LaGrange, Illinois
MIL-S-3786:
MIL-S-6807:
MIL-S-8805:
MIL-S-83504:
MIL-S-3786:
MIL-S-6807:
MIL-S-8805:
MIL-S-83504:
MIL-S-3786:
MIL-S-6807:
MIL-S-8805:
MIL-S-83504:
UL Standard:
1000 megohms
(for plastic insulation)
Not specified
2000 megohms
1000 megohms
10 megohms
(for plastic insulation)
3 megohms after
drying
10 megohms
(for plastic material)
10 megohms
1000 Vac and 1 mA
maximum leakage
600 Vac RMS after life
10 microamperes
maximum leakage
1000 or 1000 plus
twice working voltage
(AC) RMS and 1mA
maximum leakage
500 Vac and 1 mA
maximum leakage
900 Vac without
breakdown (UL
Standard (dependent
on test)
withstand a high voltage. Voltage breakdown
describes the point at which an arc is struck and
maintained across the insulating surface with
the voltage applied between the conducting
members.
ADDITIONAL LIFE FACTORS
Effect of Loads
On any switch, an arc is drawn while breaking a
circuit. This causes electrical erosion of the
contacts. This erosion normally increases contact
resistance and generates wear products. These
wear products contaminate insulating surfaces.
This reduces dielectric strength and insulation
resistance.
The amount of this erosion is a function of
current, voltage, power factor, frequency and
speed of operation. The higher the current is, the
hotter the arc and the greater the erosion. The
higher the voltage is, the longer the arc duration
and the greater the erosion.
Inductance acts as an energy storage device.
This returns its energy to the circuit when the
circuit is broken. The amount of erosion in an
inductive circuit is proportionate to the amount of
inductance. Industry standard test inductance
as described in MIL-I-81023 is 140 millihenries.
Other test loads include 250 millihenries and 2.8
henries.
Frequency can also affect erosion. The arcing
ends when the voltage passes through zero. To
a certain extent, the following is true. The higher
the frequency, the sooner arcing ends, the lower
the erosion.
The speed of operation affects the duration of
the arc. Fast operation can extinguish the arc
sooner. This reduces the erosion, unless the air
within the switch is completely ionized.
Actuating Force
Rotational torque is the actuating force required
to turn a rotary
positions. For pushbutton or DIP switches, it is
the force required to depress the button, or move
the actuator between positions. The actual torque
or force required depends on the design of the
switch. It varies widely from one design to another.
See appropriate MIL Specs or manufacturers
literature for typical industry values for specific
designs.
When torque or force values are specified, it is
customary to give a minimum and maximum
value. During life, two offsetting factors may
occur to change the initial value. Relaxation of
spring members will tend to lower torque or force
values. Wear or “galling” of mating surfaces,
however, may tend to increase these values.
Typical end of life specifications may require the
switch to fall within the original range. Or, they
may specify a maximum percentage change
from original value. For example, “the rotational
torque shall not change more than 50% from its
initial value.
60525-5997 • USA • Phone: [phone] • Fax: [phone] • www.grayhill.com
Rotary Switch Engineering Information
switch through the various
Effect of Ambient Temperature
Temperature extremes may affect switch
performance and life. Very high temperatures
may reduce the viscosity of lubricants. This
allows them to flow out of bearing areas. This
can hasten mechanical wear of shafts, detents,
plungers, and cause early mechanical failure.
Contact lubricants are sometimes used. Too
little lubrication can result in a high rate of
mechanical wear. Too much lubrication flowing
from other bearing areas can adversely affect
dielectric strength and insulation resistance.
Through careful design and selection of
lubricants most manufacturers attempt to
minimize these affects. Nevertheless, continual
operation in high ambient temperatures will
shorten the life of a switch regardless of design.
Extremely low ambient temperatures may also
create problems. Low temperatures may cause
an increase in the viscosity of the contact
lubricant. Higher viscosity can delay or prevent
the closing of contacts, causing high operating
contact resistance. Under certain atmospheric
conditions, ice may form on the contact surfaces.
This also causes high and erratic contact
resistance.
Neither of these conditions may materially
reduce the life of the switch. However, it may
cause unsatisfactory operation. If the voltage of
the circuit is high enough, it can break down the
insulating layer. Some current will flow through
the high resistance contacts. A local heating
action is created, which tends to correct the
condition in a short period of time.
Switches with high contact pressures may
minimize the low ambient temperature effect.
This is particularly true if the application calls for
switching signal level voltages and currents.
Effects of Altitude
In high altitudes, barometric pressure is lower.
Low pressure reduces the dielectric strength of
the air. The arc strikes at a lower voltage and
remains longer. This increases contact erosion.
Switches for use in high altitudes will therefore
require de-rating in terms of loads and/or life.
Effects of Duty Cycle
Mechanical life testers cause accelerated life
testing. Testers operate switches at a rate of
approximately 10 cycles per minute. This rate is
greatly in excess of normal manual operation in
equipment. It constitutes a severe test of the
switch.
Lubricants do not have an opportunity to
redistribute themselves over the bearing
surfaces at this duty cycle. The contact heating
caused by arcing does not have a chance to
dissipate.
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