Can someone explain what a tacho does in a manipulator (crane)?

Question

Our manipulator broke down last night and we had to call in repairers , they said that the tacho had gone!!!, what the hell does a tacho look like and what does it do? and how can they tell it had broke?

you are quite wrong pascalde.....

Answer 1

A tacho (tachometer) is a general description for a device that measures distance. In your manipulator I expect it measures the distance the cables have traversed. It could be a small wheel in contact with the drive shafts or possibly the cables. When the drive shaft or cables move, the tacho wheel turns and gives an electrical signal to unit that is part of the control system. Failure could be mechanical, i.e. not turning properly, or electrical, i.e. not giving the correct output.

We use tachos at work to measure the size of die-cut cells whilst running on our rotary die cutting machines. They are accurate to a few microns and help us to manipulate machine settings to give the correct results.

Answer 2

There is of course another type of tacho, the tacho generator.

If it is a crane of heavy lifting capacity, then the tacho generator may be used to provide accurate motor speed feed back to an electrical frequency drive. This device will enable far more accurate control of the crane drive and levelling abilities

Answer 3

the tacho (tachograph) is small electronic device that measures how long a machine has been working for to ensure the operator is taking the correct amount of breaks. specified by the EU working times directive.
the operator should be inserting a paper disc into the tacho daily and pressing buttons when he starts and finnishes breaks and also when the crane is switched off. the paper discs are meant to be handed in to the employer every day and kept, so that they can be checked by health and safety inspectors.
they are purely safety measures to ensure operators are not becomming overtired when using heavy plant.
they are normally in the dash board.