Up for sale is an Endevco 7240C charge accelerometer. At 4.8gm it’s designed for high amplitude vibration measurement on light structures at frequencies up to 20kHz.

 

If you're not familiar with Endevco they are a high-quality transducer manufacturer (now part of PCB) widely used in aerospace and defence industries and on a level with B&K for their vibration products, in fact B&K sold Endevco products as part of their portfolio around twenty years ago.

 

Weighing in at just 4.8gm it’s a high amplitude measurement accelerometer usable for sinusoidal vibration levels up to 1000g peak in a temperature range -55°C to +260°C and a specified frequency range of 1 to 20,000Hz. Common with other miniature accerelometers it has an M3 microdot connector (see my other auctions for a cable) but, surprisingly it has a standard 10:32 mounting stud.

Because of its low weight it’s suitable for making measurements on lighter weight structures where a larger transducer would impose mass loading. Size and performance-wise it’s similar in weight and sensitivity as the B&K 4505-A but with a wider frequency bandwidth.

 

This accelerometer is in perfect condition, with no marks on the casing, and checks out with an actual sensitivity of 2.7 pC/g which is well within the manufacturers tolerance with the lower limit being 2.3 pC/g.

 

I measured the frequency response of the accelerometer against my reference accelerometer using a step sine test on my 4810 shaker (neither of which are part of the sale) and it measures well within the ±5% limits, 1Hz to 10kHz, and the ±1dB limits, 1Hz to 20kHz specified by Endevco (Endevco typical response is in the last picture). Its performance would be even better than my test setup indicates as we are approaching a resonance in my 4810 and the limits of my 8305 reference accelerometer due to the combined weight of both transducers.

 

Setting the price for this transducer at £115. You can still buy a 7240C from Endevco (now part of PCB) but I have no idea how much it would cost but it would be more than ten times my price. The accelerometer in the pictures is the only thing for sale as it has no box or documentation.

 

I want you to be confident in the quality of the products I supply and will not sell anything as 'working' unless we have thoroughly tested it and I will tell you how I did it. I've seen many items for sale which are listed as 'tested' and 'working’ where a cursory glance at the pictures would tell you that correct functionality was impossible. We will not sell anything we cannot test except for spares.