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vfd turns on hertz but no voltage or amperage

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Location
Florida
Occupation
Industrial Technician/Electrician
Working with an ABB ACS355 drive and when I turn it on, it comes up to 36.8 hertz which is correct but I am not getting any voltage out to the motor or amperage output. I have already ordered a replacement drive but wanted to know if anyone could educate me on what is wrong internally with my drive. When it comes up to the hertz, it just sits there with no output and no faults. I have checked all the wiring going out and ohmed out the motor and everything there checked good. Any insight would be appreciated.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I have seen this a few times. It has always been a misconfigured drive or a drive that is not being controlled correctly. My guess would be nothing wrong with the drive. But hard to tell with the minimal information you have provided.
 
Location
Florida
Occupation
Industrial Technician/Electrician
Ok. Existing install. It ramps up to 38.6 hertz. That is the current setpoint we have been running. It has no voltage going out. 480 volts coming in. Was running before we had to replace the belts. Belt driven design to gearbox for a plastic reclaim extruder.
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
Ok. Existing install. It ramps up to 38.6 hertz. That is the current setpoint we have been running. It has no voltage going out. 480 volts coming in. Was running before we had to replace the belts. Belt driven design to gearbox for a plastic reclaim extruder.
Jraef may well have have spotted it - no voltage out to the motor suggests that it is disconnected.
 
Location
Florida
Occupation
Industrial Technician/Electrician
Ok so I got on here thinking people would actually help here. All the basics have been checked and verified. Motor is hooked up. Motor has been ohmed and checked for any leg grounded and it is good. All safety switches are working and it turns on like it is supposed to but does not send voltage out from the drive. Voltage is being checked with a fluke 87V. Pretty sure that meter is pretty accurate. If you don't know the answer or have never seen a situation like this then why even respond. I have been doing industrial electrical work for over 20 years and this is the first time I ran across an issue like this. Was just hoping someone would actually be helpful with real answers.
 

Besoeker3

Senior Member
Location
UK
Occupation
Retired Electrical Engineer
Ok so I got on here thinking people would actually help here. All the basics have been checked and verified. Motor is hooked up. Motor has been ohmed and checked for any leg grounded and it is good. All safety switches are working and it turns on like it is supposed to but does not send voltage out from the drive. Voltage is being checked with a fluke 87V. Pretty sure that meter is pretty accurate. If you don't know the answer or have never seen a situation like this then why even respond. I have been doing industrial electrical work for over 20 years and this is the first time I ran across an issue like this. Was just hoping someone would actually be helpful with real answers.
We are trying to help!
If there is no voltage on the motor that's the starting point.
 

Electromatic

Senior Member
Location
Virginia
Occupation
Master Electrician
We are trying to help but can only do so much at a distance on a forum.

Can you confirm that the drive is getting a RUN command -- either locally or remote?
Are there safety inputs? If you were working on the belts, could there be a guard switch that needs to be closed or reset? I don't know if that would show as a "fault" on the drive.
If the drive wasn't really touched, but just the equipment it operates, I'd tend to look for problems other than the drive.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Ok so I got on here thinking people would actually help here. All the basics have been checked and verified. Motor is hooked up. Motor has been ohmed and checked for any leg grounded and it is good. All safety switches are working and it turns on like it is supposed to but does not send voltage out from the drive. Voltage is being checked with a fluke 87V. Pretty sure that meter is pretty accurate. If you don't know the answer or have never seen a situation like this then why even respond. I have been doing industrial electrical work for over 20 years and this is the first time I ran across an issue like this. Was just hoping someone would actually be helpful with real answers.
Talk about an attitude...
With the information you gave it could have been anything that was posted.
If you called a buddy and told him what you posted to us, you don’t think he would have started with “disconnect open?”
If all you did was change belts, why suspect the drive if it was working?
 
Location
Florida
Occupation
Industrial Technician/Electrician
The drive is on and ramps up to 38.6 hertz. Everything else is good. Run command is there. The drive says it is running and indicates the hertz. Scroll thru the display options and shows 0 amps. Checked the amps with a fluke 33 and it shows 0 amps. Checked output voltage at U2 V2 W2 and shows no voltage phase to phase or phase to ground. Input voltage on U1 V1 W1 is 480 volts. Everything is working correctly on the machine and the drive except not sending voltage out from the drive.
 

paulengr

Senior Member
Ok so I got on here thinking people would actually help here. All the basics have been checked and verified. Motor is hooked up. Motor has been ohmed and checked for any leg grounded and it is good. All safety switches are working and it turns on like it is supposed to but does not send voltage out from the drive. Voltage is being checked with a fluke 87V. Pretty sure that meter is pretty accurate. If you don't know the answer or have never seen a situation like this then why even respond. I have been doing industrial electrical work for over 20 years and this is the first time I ran across an issue like this. Was just hoping someone would actually be helpful with real answers.

What is the voltage (phase to phase, true RMS) at the drive terminals (U, V, W)? If not zero then the motor is not connected to the drive.

Do you have DC bus voltage? Seems likely since the display is up but test between whichever terminals are labeled + and - for both DC and AC. DC should be around 145% of the line AC voltage. AC should be under 10 V. This proves you have DC power (rectifier is working).

Does the drive have an enable or safe off function? If so and it is “off” some of these electrically kill power to the thyristor. Check very closely because some of these are independent of the run command.

And as stated it sounds like a command problem or a control signal issue. Make sure you have settings saved. Pull terminal strips or disconnect control wiring. Factory default the drive then do a quick config (minimal) for keypad only control, no IO. Try to start/run the motor. If it doesn’t drive or hardware is defective. If it runs then it’s a configuration problem. I usually try to enable configuration one step at a time and test each signal as I go.

I can’t remember on ABB but on AB they have a software/hardware enable dip switch. In hardware enable you must have a jumper or relay on the right pins. In software mode this can be disabled and often is. So if you switched drives it might be a dip switch issue. Also there xare sometimes jumpers for internal/external 24 VDC and current sourcing/sinking. Make sure all jumpers and dip switches are identical. Go into the IO settings menus and check what each input should do then the monitoñr menu and check what inputs are seen.

Another one that messed me up recently is some LSIS brand drives expected a NC input for a remote reset button. Because of that you must have either a jumper or NC push button. Same with stop inputs. Also many drives have a “safe on” function where if the drive powers you with a run command on, it ignores it until it sees an off to on transition.

Lots of ways this can happen and not just a bad drive.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Twenty years makes 'you a babe in arms' relative to some of the posters here.
We don't know your skills or what you have done.
We get enough posts that never reply after pages of suggestions. Make me think that someone had a "duh moment" and was too embarrassed to answer back. None of us learn that way.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
The drive is on and ramps up to 38.6 hertz. Everything else is good. Run command is there. The drive says it is running and indicates the hertz. Scroll thru the display options and shows 0 amps. Checked the amps with a fluke 33 and it shows 0 amps. Checked output voltage at U2 V2 W2 and shows no voltage phase to phase or phase to ground. Input voltage on U1 V1 W1 is 480 volts. Everything is working correctly on the machine and the drive except not sending voltage out from the drive.
Thank you.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Twenty years makes 'you a babe in arms' relative to some of the posters here.
We don't know your skills or what you have done.
We get enough posts that never reply after pages of suggestions. Make me think that someone had a "duh moment" and was too embarrassed to answer back. None of us learn that way.
I have dust on some old tools that is older than 22 years...
 
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