Products

Specifications

Operating Temperature:

Ball Bearings  :  -40°C to + 70°C (-40°F to + 158°F) @ 65% RH
Sleeve Bearings  :  -25°C to + 70°C (-18°F to + 158°F) @ 65% RH

Bearing System Life Code:

2 Ball Bearings  :  D  :  70,000hours @ 25°C and 65% RH
1 Ball/1 Sleeve  :  C  :  50,000hours @ 25°C and 65% RH
1 Ball Bearing  :  B  :  50,000hours @ 25°C and 65% RH
Sleeve Bearing  :  S  :  30,000hours @ 25°C and 65% RH

Storage Temperature

All  :  -40°C to +70°C, 35% to 85% RH

Impeller/Frame

Material  :  PBT, 15% Glass Filled
Flammability  :  UL94V-0
Color  :  Black-standard, Clear or colored-optional

Lead Wires

Rating  :  UL 1077 or UL 1571, Glass A 105°C
AWG  :  26 or 28
Wire Length  :  200+/- 10mm standard
Strip Length  :  5.0+/-2.0mm standard, stripped and tinned
2 Wire Standard Red (+), Black (-)
3rd Wire Options

Yellow
None
Locked Rotor Alarm
Tachometer/Speed Sensor (2 pulses per revolution)
Exterior Thermal Sensor

Insulation Resistance

Standard  :  10MΩat 500 VDC minimum (frame to leads)

Dielectric Strength

Standard  :  700VAC (50/60Hz) for 3 second with <0.5 mA allowable between frame and leads

Noise Data

Standard  :  All noise readings are taken in dBA at 1 meter from air intake side, fan suspended in a semi-anechoic chamber (<18dBA max)

Protection

Locked Rotor  :  Standard Feature meets UL standard 72 hour test
Reversed Polarity  :  Standard Feature
Auto Restart  :  Optional
Thermal Sensor  :  Optional, fan hub mounted or exterior third wire input

Shock and Vibration

Vibration  :  Meets 5 minutes for X, Y and Z axes at

a. 5-30Hz with, 0.04G peak to peak amplitude
b. 30-500Hz, 2G peak to peak amplitude

Shock  :  Meets 50G at 11ms, half-sine, twice for X, Y and Z axes

DC Fan Catalog Part Numbering System

Bearing System Selection

Fan Bearing System Selection

The following bearing systems are available in the DC Fan product line offering:

Bearing System	Order Code	Lifetime Hours	Noise	Relative Cost
Sleeve	S	30,000	Low	Lowest
One Ball/ One Sleeve	C	50,000	High	1.8
One Ball*	B	50,000	High	1.7
Two Ball	D	70,000	Highest	2.4

Each bearing system has its own merits, performance and cost. These are explained in the following sections. An important part of fan selection is weighing the cost versus the expected lifetime of the bearing system.

*Not all bearing systems are available on all fan sizes. For example the One Ball bearing system is only available standard on the 30x30x7 mm fan where the thin 7mm thick profile is required.

Bearing system life expectancies are rated at 25C, for increased operating temperatures the life expectancy must be de-rated, this is usually done through MTBF calculations and accelerate3d testing at higher temperatures per MIL-HDBK0217D.

Sleeve Bearing System

A sleeve bearing, also known as a bushing, is the shorter life bearing system but also has a very low cost. The sleeve and shaft themselves are traditional low cost dissimilar low friction materials and the sleeve is often oil bearing. The sleeve and shaft have a large common surface contact area and exhibit good shock and vibration resistance plus low rotational noise.

Ball/Sleeve Bearing System

The Ball/Sleeve bearing system is a hybrid between the two ball system and the sleeve bearing system. Since miniature precision ball bearings are a costly component of any fan system; this was the industry s first attempt to reduce cost without reducing life expectancy to that of the standard sleeve alone. The system use only one of the costly precision miniature ball bearings and one smaller traditional sleeve, and offers some of the advantages of both systems. Negatives of the use of a ball bearing are increased bearing noise (usually only discernable at less than a 1 meter industry test standard) and greater susceptibility to impact damage (due to the high point loads of the ball bearing themselves).

It is a more difficult system to assemble and control and sometimes not favored by fan manufacturers. Modern bearing technology for coated and lubricated sleeve systems has advanced considerably, but this bearing system still remains popular today.



The one ball bearing system is used primarily where mechanical space is very limited.

Vette Offers this bearing system as a standard only for fans where the frame thickness is very small, such as on the 40x40x7 fan. The susceptibility of impact damage (due to the high point loads of the ball bearings themselves) is lessened on small fans due to the low impeller mass.

Two Ball Bearing Systems

The two ball bearing system is the industry leader for both long life expectancy at 80,000 hours, but also has the highest cost and noise (at close ranges). The susceptibility to impact damage is less than that of a One Ball system but still far higher than that of a sleeve. On advantage of Ball Bearing systems is that due to the small point load of the balls, they require less power to start rotation as they have less stiction (starting friction) than a sleeve bearing. Two Ball bearing systems are used where long system life is important.



Bearing Lubrication, Wear and Failure
Typically fans ultimately die because of bearing failure. This is why bearing selection is so important. Bearing failure is normally due to bearing wear and wear is typically from either lack of lubrication or direct damage.

Direct damage can impact or shock to the fan itself. Ball bearing system with their high point loads are susceptible to this kind of damage. However ball bearing systems are relatively well sealed and lubricated hence their longer life.

Sleeve systems, whether of the basic oil laden bushing type or the more exotics with coatings or seals or lubricants, etc typically will lose lubrication at some point and run dry, leading to wear.

Air floatation bearings will tend to clog with worn bearing surface materials. All fans typically will get noisier and rotate slower as the bearing systems wear and tear. This is a good indicator of pending bearing failure.

Measurement of Air Volume and Static Pressure

Determination of the air performance curve is obtained by using the double chamber method based on AMCA standard. The difference between the pressures before and after the nozzle (differential pressure Pn) is measured to obtain the airflow at the nozzle and the different pressures between those in the two chambers (static pressure Ps). The airflow is calculated from the differential pressure by using equation (A). The auxiliary blower cancels out the aerodynamic resistance

Q= 60AV....(A)
Where

Q: Air flow rate (m³ min)
A: Nozzle sectional area = F/4 D² (M²)
V: Average flow velocity from nozzle

r: Specific gravity (kg/m³) of air (r=1.2kg/m³ at 20°C, 1atm)
g: Gravitational acceleration = 9.8m²/S
Pn: Differential pressure (mm H₂O)
Ps: Static pressure (mm H₂O)

Maximum air flow: When opening the nozzle and absorbing the air using the auxiliary blower to make the static pressure zero (Ps=0), the differential pressure (Pn) between chamber A and chamber B will be at its maximum. The air flow obtained by applying the differential pressure (Pn) to the above equation can be called the maximum air flow.

Maximum static pressure: As shown in the figure, when closing the nozzle, the pressure in the chamber A will be at its maximum. This differential pressure (Ps) between the air pressure and the pressure in the chamber A can be called the maximum static pressure.

Noise Level Data

The measurement of noise levels are made in accordance with CNS 8753 (which is very close to DIN45635) which is being tested in a sound proof chamber with a sound level Lp<18dBA.

An elastic mount supported microphone is placed 1 meter from the center line of the fan during the test.

The fan is running without any resistance to airflow.

   

Sound Pressure Level (SPL) is environmentally dependent and is defined as SPL=20 log 10p/Pref, and Sound Power Level (PWL) is defined as

PWL = 10 log 10W/Wref....
Where

P = Pressure
Pref = A reference pressure
W = Acoustic power of the source
Wref = An acoustic reference power

Fan noise data is usually plotted as Sound Pressure Level against the octave frequency bands.

   

Tachometer Signal & Alarm Signal

Pulse Sensor (2 Pulse per revolution signal)
Pulse sensors are used for detecting the rotational speed of the fan motor.

Output Waveform	Output Circuit Open Collector
T1-4=(1/4)To T1-4=(1/4)To=60/4N(s) N=Fan Rotational Speed (min)	If fan locked on VH, signal stays locked. If fan locked on VL, signal stay at VL for a few hundred MS, then moves to VH.

Lock Sensor (Locked rotor alarm signal)
Lock sensors are used to detect if the motor is in operation or stopped

Output Waveform	Output Circuit Open Collector

DC Fan Selection Guide

DC Fan Selection Guide 1
Model	Frame Size	Available Options							Air Flow Range		Static Pressure Range		Frame Size
Axial Fan	(mm)	Auto Restart	Tach	Locked Rotor Alarm	Thermal Sensor Speed Control	PWM Motor Pulse Width Modulation	Connector Selection	Custom Colors	CFM low	CFM high	mm H2O low	mm H2O high	dBA low	dBA high
A3010	30x30x10	Y	Y	Y			Y	Y	1.79	3.22	1.97	4.17	24	32
A4007	40x40x07	Y	Y	Y			Y	Y	2.73	3.86	0.89	1.75	24	30
A4010	40x40x10	Y	Y	Y			Y	Y	2.6	5.26	0.77	3.17	25	36
A4020	40x40x20	Y	Y	Y			Y	Y	5.36	8.47	2.03	4.69	25.75	37
A4510	45x45x10	Y	Y	Y			Y	Y	4.71	6.89	0.96	1.79	24	31
A5010	50x50x10	Y	Y	Y			Y	Y	7.21	11.19	1.58	2.71	25	34
A5015	50x50x15	Y	Y	Y			Y	Y	8.13	11.91	2.07	4.04	26.5	34.8
A6010	60x60x10	Y	Y	Y			Y	Y	13.33	18.13	1.83	3.04	31.5	36.5
A6015	60x60x15	Y	Y	Y			Y	Y	13.97	20.16	2.16	4.1	27.5	36.25
A6020	60x60x20	Y	Y	Y	Y	Y	Y	Y	12.46	18.03	2.21	4.36	27	36
A6025	60x60x25	Y	Y	Y	Y	Y	Y	Y	15.86	21.53	3.02	5.32	31	40
A7010	70x70x10	Y	Y	Y			Y	Y	16.62	22.66	1.47	2.36	29	36
A7015	70x70x15	Y	Y	Y	Y	Y	Y	Y	20.78	29.2	1.88	3.59	32	37.5
A7025	70x70x25	Y	Y	Y	Y	Y	Y	Y	20.04	30.01	1.81	3.71	28.6	39.2
A8010	80x80x10	Y	Y	Y			Y	Y	13.3	22.61	0.69	1.58	24	31
A8015	80x80x15	Y	Y	Y	Y	Y	Y	Y	27.72	37.15	2.77	4.59	34.4	41.1
A8020	80x80x20	Y	Y	Y	Y	Y	Y	Y	22.28	33.83	1.19	2.46	27	35
A8025	80x80x25	Y	Y	Y	Y	Y	Y	Y	23.7	33.46	1.62	2.98	28	36.3
A9225	92x92x25	Y	Y	Y	Y	Y	Y	Y	36.78	51.54	1.59	2.91	30	37
A1225	120x120x25	Y	Y	Y	Y	Y	Y	Y	61.83	91.21	2.21	4.26	32	39

DC Fan Selection Guide 2
Model	Frame Size	DC Voltage				Bearing System Selection				Safety Agency
Axial Fan	(mm)	5	12	24	48	Standard Sleeve 30K	1Ball 50K MTBF	1B/1S 50K MTBF	2Ball 70K MTBF	UL Approved	Grams
A3010	30x30x10	Y	Y			Y		Y	Y	Y	11.5
A4007	40x40x07	Y	Y				Y			Y	11.5
A4010	40x40x10	Y	Y			Y		Y	Y	Y	14
A4020	40x40x20		Y	Y		Y		Y	Y	Y	23.5
A4510	45x45x10	Y	Y			Y		Y	Y	Y	15.6
A5010	50x50x10	Y	Y			Y		Y	Y	Y	17.1
A5015	50x50x15		Y	Y		Y		Y	Y	Y	24.5
A6010	60x60x10	Y	Y			Y		Y	Y	Y	24
A6015	60x60x15		Y	Y		Y		Y	Y	Y	24.5
A6020	60x60x20		Y	Y		Y		Y	Y	Y	48.5
A6025	60x60x25		Y	Y	Y	Y		Y	Y	Y	52.8
A7010	70x70x10		Y			Y		Y		Y	40
A7015	70x70x15		Y	Y		Y		Y	Y	Y	44.8
A7025	70x70x25		Y	Y	Y	Y		Y	Y	Y	63
A8010	80x80x10		Y			Y		Y		Y	37
A8015	80x80x15		Y	Y		Y		Y	Y	Y	44.5
A8020	80x80x20		Y	Y		Y		Y	Y	Y	53.6
A8025	80x80x25		Y	Y	Y	Y		Y	Y	Y	63
A9225	92x92x25		Y	Y	Y	Y		Y	Y	Y	74
A1225	120x120x25		Y	Y	Y				Y	Y	140