| 1. What is the
life expectancy of a fan? |
| We publish
the life expectancy for all our fans. This is expressed in terms of L10
life. L10 refers to the time at which in a large population, 90% of the
air moving devices will still be operative. |
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| 2. What is airflow? |
| Airflow is
the volume of air moving through a blower or duct. Units of measure are
cubic feet per minute (CFM), liters per second (LPS) or cubic meters per
hour (M3H). |
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| 3. What is static
pressure? |
| Static pressure
is the difference in air pressure between the suction side and pressure
side of the blower. Unit of measure is inches of water volume (in. wc)
or Pascals (Pa). |
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| 4. What are
air performance curves? |
| Air performance
curves are graphs showing air flow characteristics: airflow (cfm) versus
static pressure (in. wc) and airflow (cfm) versus blower speed (rpm). |
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| 5. Are your
fans dynamically balanced? |
| Yes, in two
planes while running. |
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| 6. What is the
system operating point? |
| The system
operating point is the point of operation of the air mover on its air
performance curve. It is described by an airflow and static pressure point.
The operating point is that point on the air mover performance curve where
the system resistance curve crosses the air performance curve. |
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| 7. What is system
impedance? |
| System Impedance
is the resistance to air flow when moving air through an airflow system.
Examples: air filters, air grilles and abrupt changes in flow direction. |
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| 8. What are
fan laws? |
| Fan laws
are a family of mathematical relationships that allows the calculation
of new operating characteristics from known system conditions. |
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| 9. What is motor
insulation? |
| Motor insulation
systems are the materials used for wire and coil insulation and are classified
according to the highest temperature at which normal service life can
be expected. There are five motor temperature classifications: A (1050 C), E (1200 C), B (1300 C), F (1550 C)
and H (1800 C). The maximum temperature rating is based on
the temperature rise of the coil winding plus the ambient air temperature
at the motor. |
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| 10. What’s the
farthest distance the NTC resistor can be from a Variofan? |
| Fifteen (15)
feet. You must use a twisted pair of 24 gage wire. |
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| 11. What does
"FPS" stand for? |
| Fan performance
sensor. |
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| 12. What does
"TTL" stand for? |
| Transistor-transistor
logic. |
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| 13. Do plug and
cord sets work in 115 and 230 volts? |
| Yes |
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| 14. How do you
hook up a Variofan? |
| Red is plus,
black is ground, NTC resistor goes between green and ground. |
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| 15. What does
"V-A" stand for? |
| Value-added.
This is when ebm customizes an air mover by adding terminals, threaded
inserts, sheet metal, etc., to aide in ease of assembly for the end user/customer. |
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| 16. Can a solid
state speed control be used with mvl blowers? |
| Yes, however,
not all speed controls are designed the same, so check with our application
engineers to insure trouble-free operation. |
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| 17. Can the motor
position on the crossflow blower be rotated? |
| Yes. Most
crossflow blowers can have the motor rotated in increments of 900.
Motor rotation, if required, should be performed at ebm Industries as
a value-added service. |
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| 18. Do the blower
motors have agency approval for the US and Canada? |
| Yes. Most
models are UL and cUL recognized or CSA certified for use in the US and
Canada. Please check with an ebm-papst applications engineer for questions about
the approval status of specific models. |
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| 19.What is the
minimum recommended starting voltage for AC blower motors? |
| In general,
seventy-five (75%) percent of the rated voltage of the blower motor is
required to reliably start the motor. |
| Example:
Minimum starting voltage: 111 x .75 = 86V |
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| 20. What is the
minimum recommended clearance between the stator of an mvl motor and any
adjacent sheet metal? |
| 7/16"
air gap, otherwise electrical performance of motor will be adversely affected. |
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| 21. Are the blowers
date coded? |
| Yes. ebm
(mvl) products have a three or four digit number on the lower right corner
of the label on the blower housing. |
| Examples: |
| 029 = week
2, 1999 |
| 4999 = week
49, 1999 |
| 0500 = week
5, 2000 |
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| 22. Can all 60
Hz blower motors operate on a frequency of 50 Hz? |
| No. Unless
the motor is specifically designed to operate at both 50/60 Hz, each motor
must be evaluated for the application on a case-by-case basis. |
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| 23. Are the blowers
available with European voltages and approvals? |
| Yes, many
models are available that are manufactured to European standards with
equivalent air delivery. Models that are not currently designed with European
voltages can be supplied with minimum production order quantities. Most
models designed for European voltages are built to VDE specifications. |
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| 24. What is a
motor? |
| A motor is
a device that converts electrical energy into mechanical energy. A motor
can operate on direct current (DC) or alternating current (AC) voltage
supply, not both. |
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| 25. What is an
AC induction motor? |
| The single
phase AC induction motor is a common design for fractional and subfractional
motors. The motor consists of two basic electrical assemblies: the stator
and the rotor. The stator is the primary electrical circuit that induces
a current in the secondary electrical circuit, the rotor. The combined
electromagnetic effect of the two circuits produces rotation of the rotor. |
| |
| There are
two types of single phase AC induction motors commonly used for direct
fan applications: shaded-pole and permanent split capacitor. |
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| 26. What is a
shaded-pole motor? |
| Shaded-pole
motors are simple in construction and the least expensive for subfractional
and fractional horsepower applications. The motors typically operate within
an efficiency range of 20% to 40%. The components that make up a shaded-pole
motor are the stator, the main winding (coil winding), the auxiliary winding
(shading coil) and the rotor. |
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| 27. What is a
permanent split capacitor motor? |
| Permanent
split capacitor motors (PSC) motors, like all capacitor motors, require
an external capacitor to be connected to the motor circuit. The motor
typically operates within an efficiency range of 60% to 70%. The components
that make up a permanent split capacitor motor are the stator, the main
winding, the auxiliary winding, the capacitor, and the rotor. |
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| 28. What are
the differences in motor speeds? |
| Induction
motors are either asynchronous or synchronous speed motors by design.
Synchronous motors operate at a constant speed with or without a load
applied to the shaft. Asynchronous motors operate at a variety of speeds
and are greatly affected by the load applied to the shaft. |
| A synchronous
speed induction motor will operate at 3600 rpm for a 2-pole motor, 1800
rpm for a 4-pole motor and 1200 rpm for a 6-pole motor using 60 Hz input
power. |
| An asynchronous
speed induction motor will operate at significantly lower speeds compared
to synchronous motors with the same number of poles. |
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| 29. How do you
change speed motor control? |
| The speed
of an AC induction motor can be changed by a number of methods. In addition
to changing the design of a motor, common approaches to speed control
are changing the applied voltage or changing the applied frequency. |
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| 30. How can you
change the voltage? |
| A reduction
in motor voltage can be accomplished with a resistor, variable speed AC
transformer, or a solid state speed control. |
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| 31. How do you
change the frequency? |
| This technique
is not commonly used for ebm’s products. |
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| 32. What is a
brushless DC motor? |
| A brushless
DC motor is a DC motor that has commutation accomplished by electronic
circuitry instead of brushes. Since there are no brushes to wear out,
the brushless DC motor has a life span equal to or greater than an AC
motor. |
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| 33. What is a
backward curved impeller? |
| A backward
curved impeller (BCI) is a centrifugal air moving device (wheel) with
blades inclined in the direction opposite the direction of rotation. Such
impellers can work without the aide of a specially designed scroll housing. |
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| 34. Does ebm
build fans, blowers, or motors with moisture or corrosion protection? |
| Yes, ebm
manufactures a variety of fans, blowers, and motors built with materials
that offer moisture and corrosion protection: plastics, coated steels,
and aluminum or stainless steel alloys are used for scroll housings, impellers,
and fan shafts. Moisture protected motors are built to an Internal Protection
Classification of either IP44 or IP54. |
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| 35. How is fan
life defined? |
| The air moving
industry typically rates fan life using two terms: L10 life of the bearing
and MTBF of the electronic components. |
| L10 life
is defined as the number of hours after which 10% of the fans in operation
would be expected to experience bearing failure. This number is obtained
using fan life test data and Weibull function statistical analysis to
obtain a failure distribution prediction. Bearings usually fail because
of lubricant degradation over time, which is greatly affected by the ambient
temperature in which the fan is operating. This is why bearing L10 life
numbers are always provided at a specific ambient temperature. |
| MTBF (mean
time between failures) predications are based on assumed constant failure
rates over the useful lifetime of electronic components like resistors,
capacitors and semi-conductors. These predictions are usually based on
MIL-HDBK-217 or Bellcore TR-332. Sometimes requests are made for the MTBF
of the complete air mover assembly. However, because mechanical or electromechanical
components like bearing and motors do not have constant failure rates
over time, this would not be a valid calculation |
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| 36. Do you have
a thermostatically controlled fan? |
| ebm has fans
that can be controlled by a thermistor (a device that changes resistance
as temperature changes). |
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| 37. How do you
read an air performance curve? |
| The vertical
axis (Y axis) is pressure (inches water or pascals). The horizontal axis
(X axis) is flow (CFM or M3H). The curve displays the fan delivery characteristics
of specific pressure/flow points. |
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| 38. What are
some general guidelines on mounting fans and blowers? |
| Fans with
sleeve bearings generally need to be mounted with the shaft horizontal.
Exceptions can be discussed with our engineering staff. Ball bearing fans
can mount in any orientation. |
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| 39. What is an
IP rating? |
| IP rating
is an international standard for rating motors for the effects of dust. |
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| 40. Can I repair
the blower/fan myself? |
| No. |
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| 41. Does ebm-papst
sell replacement parts? |
| No. |
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| 42. How do I
tell the air flow direction? |
| Check the
ebm-papst catalog for such information. |
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| 43. What is the
difference between air intake over discharge over struts? |
| This is a
term to describe the air flow direction moving through a fan related to
a common point, the fan motor supports or struts. |
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| 44. What is an
external motor? |
| An external
motor is a motor designed with the rotor on the outside, common construction
for brushless DC motors. |
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| 45. What’s the
maximum voltage you can apply to a blower? |
| The maximum
voltage applied is dependent upon the product and application. Consult
ebm application engineer for assistance. |
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| 46. What is the
definition of voltage range? |
| A voltage
range is the maximum and minimum voltage that can be applied to an air
mover where it will operate reliably. |
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| 47. How does
fan and blower performance change at 1,000 and 2,000 meters altitude? |
| The pressure
developed by an air moving device will change proportionally with the
air density if the RPM is kept constant. An air moving device powered
by an electric motor will change RPM with a change in altitude due to
the change in density (less load at higher altitude). This RPM change
generally will compensate for altitude changes. The exception is for AC
motors that are designed to run very close to synchronous speed at sea
level. These will not change the speed with altitude change and will therefore
produce less pressure at high altitudes. |
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| 48. Do you sell
explosion-proof fans? |
| No. |
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| 49. Into what applications do ebm-papst fans apply? |
| Our products are used in various industries and applications: Ventilation, air-conditioning and refrigeration technology, clean room technology, automotive and rail technology, medical and laboratory technology, electronics, computer and office technology, telecommunications, household appliances, heating machines and plants drive engineering. Our products are not designed for use in the aviation and aerospace industry! |
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