Browse Prior Art Database

Blower Failure Predict Circuit

IP.com Disclosure Number: IPCOM000080216D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Related People

DeSilva, DK: AUTHOR

Abstract

The present day focus on computer system reliability has prompted the need for a more satisfactory way of determining blower failure. The devices presently available will not indicate a blower failure under all conditions. The method shown herein will not only indicate a blower failure but will predict the failure.

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Blower Failure Predict Circuit

The present day focus on computer system reliability has prompted the need for a more satisfactory way of determining blower failure. The devices presently available will not indicate a blower failure under all conditions. The method shown herein will not only indicate a blower failure but will predict the failure.

The circuit of Fig. 1 shows a means by which a blower can be monitored for operation. The blower of Fig. 1 has a small spot of magnetic material 1 deposited on its impeller 2. The pickup coil 3 is mounted over this spot and detects its presence each revolution. The pickup coil transmits the signal to the input J12 of amplifier 4.

The output of the amplifier 4 is transmitted via driver 13 to the single-shot 5, where a 1 ufd capacitor 6 increases the duration of the output pulse at D10. An override gate is provided at B09, to prevent an output at D10 when power is first turned on and the blower is not up to speed. The output at D10 is transmitted to the holdover portion 7 of the single-shot. The wave shape (Fig. 2) at the input of the diode 8 shows the 1 ufd capacitor 12 being discharged every time there is a pulse from the pickup coil.

When the blower is operating normally (3000 rpm), the capacitor 12 is being discharged before it charges high enough to cause the transistor 9 to conduct. There is no output at D13 at this time. The 10K ohm potentiometer 11, in the holdover portion of the single-shot, allows for the output signal to be adjusted to a prescribed RPM alarm setting. As shown at the input of the diode 8 in Fig. 2, the potentiometer 11 is adjusted to give a...