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Teco VFD Assistance

American Locomotive

Well-known member
Joined
Jan 8, 2017
Messages
11,014
Location
Rhode Island
Hey everyone, I'm helping a buddy set up his shop. He purchased a bunch of 3 phase equipment cheap, so I've been helping him with getting setup with VFDs.

Most of my VFD experience has been with Automation Direct drives, which have amazingly comprehensive manuals that explain things in very straightforward language. We elected to go with Teco drives for his equipment, as many of the Automation Direct drives are out of stock. Unfortunately the Teco manuals, while very thorough, don't explain things that awesome.

The issue we're having is with his Teco E510 drive on his mill. It works perfectly in V/Hz mode, but we wanted to employ SLV (sensorless vector mode) for greater low-RPM power. I set up the parameters to the best that I could figure out, and did the rotational autotune. It all works fine, speed control works well, and it has good low RPM torque. The problem is there is a long delay between when you hit "Forward - Run" and when the motor actually starts turning.

When you engage forward, you can see the frequency display instantly go up to 65-70 Hz, quickly work its way down to ~0-1hz. The motor is not spinning at all during this time. Once the displayed frequency hits around 0-1 Hz, the motor will twitch a couple of times, fully engage and then follow the normal motor acceleration curve. It's about a 2-3 second delay before the motor actually starts turning from initial Run command. I cannot figure out which parameter is causing this behavior, or if it's a normal part of SLV mode. As soon as I switch the drive back to V/Hz mode, that behavior goes away. You push "Forward - Run", and it just starts out at your minimum frequency and ramps up as normal. As soon as you toggle SLV mode, it starts up doing that weird behavior - but once the motor is actually running, it works well in SLV mode.

Any ideas before I try contacting Teco?
 
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DeeKay

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Joined
Nov 25, 2020
Messages
448
Location
Colorado
Sounds kind of like you have a flying start parameter enabled.

Edit: I just looked in the manual, what do you have parameter 07-10 set at? Looks like TECO calls flying start "speed search" but it's the same thing.

Did you do the autotune with the motor un-coupled?
 
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A

American Locomotive

Well-known member
Joined
Jan 8, 2017
Messages
11,014
Location
Rhode Island
We tried auto-tune with the motor coupled and uncoupled to the mill. Same results both times.

I'll check that 07-10 parameter next time I'm over there! I agree it seemed like the VFD was trying to find the current motor speed before starting. No clue at all why it would do that when it doesn't do it in V/Hz mode. I guess a test should have been to see what it did if I canceled "Run" and then hit "Run" again while it was still spinning. Thanks for the help!
 
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