Elevator System

Hello,

What is the specification of Siemens VFD? It seems Thyristors have failure then drain much current than need. by increasing setpoint in hand-mode and check current each phase you might detect the failure phase of VFD

Regards

DBT

Motor runs fine when disconnected from the elevator? How may amps and are they low as you would expect? Balanced phases?

If so:

Drive and motor are probably good.

Something mechanical is likely to be hanging up or dragging on the elevator equipment, based on what you posted. I would look all the bearings and sheaves over real close and check for debris caught in something.

Good luck, K T

Elevator roll OK when the brake is removed.

You may consider JRaef's post below--

I hadn't considered the braking mechanism--We tried a VFD on a motor that had a mechanical brake and gave up on it--The drive couldn't develop enough torque to release the brake before faulting. I don't know much about elevators so I will leave this to someone who does.

Sorry, K T

Using drives on elevators is VERY tricky, potentially dangerous, and should not be undertaken by those not familiar with the specific challenges involved. Was this nstallation done by someone who knew what they were doing?

Is this an old or new installation?

If it's old, then the problem might be in the VFD since the motor checks out okay. It can also be in the elevator's construction. Something jamming the car?

If it's new, is the motor matched to the drive? If memory serves me right, elevator motors are high-starting current devices. Also, starting a motor with low-voltage and low-frequency will naturally increase the starting current, possibly exceeding the drive's limits.

In one non-elevator application, our VFD tripped when the brake didn't disengage fast enough. We rigged up the program so that the brakes were disengaged about a half-second before the VFD actually started.

regards,

Vulcan

You need a constant tork vfd, ran into the same problem last friday.

You need to answer a question...

Does this elevator carry people?

If the answer to this is "yes" you need to get a person who is approved by the Elevating Device legislation in your jurisdiction to repair elevating devices to check this unit out. Doing anything more then this opens you to huge possible legal and liability issues.

As JRaef has correctly pointed out... drive control on a lifting device is tricky and, again if the lifting device carries people, is best left to those authorized and capable of making these repairs.

Caution and prudence is called for.

It would help if you state more detail.

Is this a new problem developing in old equipment?

Is this a new installation?

Have any parts been replaced lately, etc?

Only you know what detail questions I could have included here, Please add as needed.