We had this Altivar 28 on our plant which was running a motor rated at 4KW / 9A.

It stopped with no fault indication. When the inverter was restarted it again stopped after 30 to 45 seconds. Multiple attempts were made to start the inverter by giving start command from the control panel but every time the inverter stopped after 30 to 45 seconds. To rule out the possibility of any overload condition, motor was decoupled but the result was the same. Then to rule out any problem in the motor, motor was disconnected from inverter but the result was no different, thereby so I am assuming the problem is with the inverter.

We've replaced it but still want to know was the actual fault.

Any clues in this regards?

Thanks

Hello. My opinion is that the Altivar inverter is not a good product.
My experiece is not big with Altivar inverters from Telemecanique, but on at least 3 acations i had to replace them with
other brands to get rid of problems. The main problem i have experienced is thath they don't manage to deliver enough
power to the motor. I have onely used the type witch has 1 phase in and 3 phase out.
It seems like Telemecanique classifies their inverters diffrently than most other brands.
E.g. an inverter from Telemecanique marked 0,75kW can't run a 0,75 kW motor on max.
On 2 cases i replaced with Hitatchi inverters and no problems since. Last time i replaced with Mitsubichi and it's also still running without problems.

This is onely my experience and i dont know if it's still so since i stoped using inverters from Telemecanique some years ago.


My advice : switch brand, and save money.

I would think that this type of inverter would have less power output than a 3in/3out model.




I am asking a simple question here, but are you sure that the run command is staying on? How is the drive starting/stopping, what is the control method?

If the inverter was repeatedly stopping after 30-45 seconds it could be a continuous overload or a problem with the supply making the bus gradually discharge, however both of these would show an error message. If it keeps stopping with no error depending on your configuration it is likely either loosing an enable signal or receiving an unwanted stop signal. If swapping the inverter has cured the problem it rules out dodgy contacts on external switches/relays leaving you with either loose terminals on the inverter (tightened up when installing new one) or an internal fault on the control card.

I noticed a reply saying that the Altivars do not seem to deliver enough power to the motor, it is worth noting that most manufacturers give their inverters 2 ratings, for heavy duty applications and light duty, for example a Control Techniques SK2401 is rated at 5.5kw heavy duty, 7.5kw light duty. This means if it is running a light duty application, say an extraction fan which starts maybe a couple of times a day with a nice long ramp and stays at constant speed when it gets there then 7.5kw is fine. If it is running an application with a lot of inertia to get moving, starting and stopping regularly or constantly varying speed then you don't want to be putting more than a 5.5kw motor on it.