ATV212 OL1/OL2 Difference

[StevenCho]

Hi all,

ATV212 has 2 types of Over Load fault which is [Motor overload] and [Drive overload].

I took a look into the difference.

But what I couldn't find any criteria that decide whether it is Motor issue or Drive Issue.

Below is FAQ answer regarding OL1 and OL2.
[OL1 : https://www.se.com/in/en/faqs/FA173124/ OL2 : https://www.se.com/in/en/faqs/FA213128/]

It said,

• OL1 is triggered when "If the current draw surpasses ITH value then it will eventually fault out on OL1 given enough time has passed."
  
  
• OL2 is triggered when "This will happen when the motor current exceeds the level programmed in the tHr parameter"

But ITH is not exist and seems ITH means tHr.

Is there anyone can explain me the difference between OL1 and OL2?

[BevanWeiss]

I'm not particularly familiar with the Altivar drives.  But this is likely something common amongst all drives.

There are two things which can heat up based on motor load (current).

1. The Motor
2. The Drive (whether VSD / Soft Starter / DOL Contactor)

The motor size and cooling dictate the first, and the drive 'frame size' and cooling dictate the second.

You can hook a 2MW motor up to a 1kW drive.  But you shouldn't expect to get 2MW of mechanical work performed from it.  It will almost certainly trip on a Drive Overload long before it reaches the thermal model of the Motor Overload.

The Motor thermal model can depend on a number of things, like the rotational speed, the bus voltage, the back EMF, the field magnetisation, and the armature current.

The Drive thermals will generally only be due to the phase current (of which a component will be 'armature current', and a component will be field current).

I would say that OL1 = Drive Overload (purely current based, which will be either an inherent current limit to protect the drive, or a customisable current which can be less than or equal to the drive protection current), whilst OL2 = Motor Overload (based on the thermal model of the motor that the drive is constantly updating).