Continous monitoring

I have a customer that wants to monitor a single point on a machine continuously for a few months. Overall only would be fine. He wants to see if theirs an increase in vibration before a bolt sheers or does it sheer without an increase.

nothing fancy.

any suggestions.

Original Post

Dear Jack 

What bolt we are talking about here? Is it a bearing housing bolt or a foundation bolt?

As if it is a foundation bolt it may not reflect in vibration if other stiffening factors are not damaged.

Mounting accelerometer close to the bolt may give early increase in magnitude and your customer may not have to run the machine up to bolt failure.

Thanks 

Rohit

I am also looking for a system that can monitor a machine continuously for a few hours/days.  Maybe with 4 or 8 channel capacity that can periodically store spectra and waveforms and display a warning/alert for the operators if vibration exceeds a certain level.

Greatly appreciate any suggestions.

Jack,

If those two sentences are the sum total of defining the problem/request, then your Customer wants something with a potentially high chance of useless results!

A small accelerometer can be attached to head of bolt with adhesive stud base or by magnet. Overall acceleration should be measured, since acceleration is proportional to dynamic force. This is the easy part!

The accelerometer can provide a 4-20 ma current output directly or via a transmitter module connected to the control room monitor. The key question is whether the machine monitor/control system can accept (at all, or without disrupting machine operation) the signal for trending and alarming. Modbus connection may also be considered. If these connections are not possible, then you need a different way to handle trending and alarms.

What is the budget and implementation schedule. I will wait for your response before going further with other options.

Walt

Jack1954 posted:

I have a customer that wants to monitor a single point on a machine continuously for a few months. Overall only would be fine. He wants to see if theirs an increase in vibration before a bolt sheers or does it sheer without an increase.

nothing fancy.

any suggestions.

There are some simple data loggers that could fit your application. You  may need though to know more details about the expected vibration signals to ensure the suitable selection.

 

These loggers are for vibration and shocks. They are battery operated and small in size. The collected data can be transferred to a computer using the common data transfer methods like a USB connection.

I do not have a first hand experience on them but I know someone who evaluted a couple of them and found them useful for basic applications.

 

Regards- Ali M. Al-Shurafa 

Yeah I agree with you Walt but he wants what he wants. I suggested that he get an accelerometer with a 4-20 ma output and feed it into the DCS or PLC. It can log an overall ever how fast he wants to. Probably can do that on less than $1000. I have done that on a Paper machine doctor blade. It worked pretty good.

What kind of alarms do you have in mind? If the bolt head actually breaks and becomes very loose or falls off, then vibration level could significantly drop (need a Low Alarm). If the force/vibration that causes bolt head failure is a short/transient event, then a slow scanning DCS or PLC may not detect the pre-failure event. I guess it depends on what the Customer expects for failure mode and wants to measure!

Walt

Add Reply

×
×
×
×