These fans will be exactly the same as what our customer has now.
They will last for approx. the same period, but this should get us out of trouble until the new fans arrive.
The new 630 fans are made with the new grill with better alignment which is much easier to do dynamic balancing.
They also have the new motor which is optimised for 460V-3 60Hz, this means it has much more safety margin with 50Hz operation. The motor also has a wider working range that better suits our applications.
Ideally the grill has been made so that the fans can be used for sucking and blowing operation with the same grill.
That means we can change motors if we need to change the air direction.
For now I would only send 3 fans to replace temporarily the faulty ones.
Once the new fans arrive all should be changed.