There are three oil pressure gauges on the ENGINE OIL panel of the Lockheed L-1011. This posting will show the interior of the pressure gauge made by SMITH in the UK. The instrument has an indicator range of 0 - 100 PSI, and is completely backlit (see image below).
This particular instrument has function inspected by Lockheed on February 19th 1074.
The instrument consists of the actual instrument core, and a casing tube with a tempered glass face plate. Two of the 4 screws on the backside that hold a plate that lock the instrument core and the casing are secured with metal safety wire. in order to get into the indicator, the safety wire needs to be cut.
The segmented ring on the backside is followed by a number of plates that apply pressure on the casing. Each plate needs to be removed in order to expose the o-ring that seals the case and the instrument.
The case was originally sealed under low pressure, in order to release the actual instrument i have to cut the tube that was used to lower the pressure in the case.
Now the instrument removes without problems.
TOP view of the instrument with the original electronics.
RIGHT hand side view:
BOTTOM view:
LEFT hand side view:
Just like the AC VOLT indicator that I showed you a few blog postings ago, this one also uses a magnetic core to deflect the needle arm, however, the indicator needle and the magnet are linked together via a fan-shaped gear.
The electronics of the instrument can be easily bent to work between 0V to +5V with about 40mA at maximum needle deflection. Hence, this instrument should be easy to drive with an I2C controlled variable potentiometer. There is no negative range on the dial, hence there is no need for an H-Bridge.
The picture below shows +3V applied to the original electronics.
No comments:
Post a Comment