Troubleshooting Soft Start Drive

[jerjwillelec]

I'm troubleshooting a Telemechanique Altistart 46 ATS46D88N soft start for a filter pump at an aquatic center...approximately 12 years old I'm estimating. After pushing the start button to run the motor, the code PhF comes up and the motor won't start. What I do know is...this code stands for phase fault yet I have 124v to ground on all three phases and 216v between each of the three. I'm finding very little troubleshooting tips in any manual I look up. I've always had pretty good luck here with all of your experiences. Any thoughts?

 

[ptonsparky]

Look for a load side phase fault.

 

[Jraef]

9.9 times out of 10, this is the result of the load on the motor being too light.

Most soft starters on the market require that the current flowing through the current sensors inside of it be at least 20-30% of the rating of the unit (varies by mfr.). That's how they determine phase loss, because they do not actually measure voltage, only current. So if AT LEAST one phase current is below that threshold, it means you have a phase loss somewhere. But if ALL 3 phases are below that threshold, the condition is still true, so it ASSUMES this is a phase loss.

You have most likely:
A) not yet connected the motor,
B) left the motor disconnect switch open
C) left a valve closed somewhere so no water is flowing and since water flow = load on a pump, the motor is unloaded and not drawing enough current to satisfy the Phase Loss trip condition.
D) a SERIOUSLY clogged filter!

I almost guarantee it...

 

[jerjwillelec]

9.9 times out of 10, this is the result of the load on the motor being too light.

Most soft starters on the market require that the current flowing through the current sensors inside of it be at least 20-30% of the rating of the unit (varies by mfr.). That's how they determine phase loss, because they do not actually measure voltage, only current. So if AT LEAST one phase current is below that threshold, it means you have a phase loss somewhere. But if ALL 3 phases are below that threshold, the condition is still true, so it ASSUMES this is a phase loss.

You have most likely:
A) not yet connected the motor,
B) left the motor disconnect switch open
C) left a valve closed somewhere so no water is flowing and since water flow = load on a pump, the motor is unloaded and not drawing enough current to satisfy the Phase Loss trip condition.
D) a SERIOUSLY clogged filter!

I almost guarantee it...

Very Interesting and does make sense...let me throw this out at ya though. Here is the whole story. You are correct that the pump is not moving any water so the motor is indeed not loaded. There are two identical 230 volt 25 HP motors for Filter Pump #1 (FP1) and Filter Pump #2 (FP2). Both motors look to be the same age at approx 12 years old. The soft starts however, are not...FP1 drive has since been replaced with a Telemechanique Altistart 48 ATS48D88YU though I'm not sure when as it was before they started calling me. The staff tried to start them a couple of days ago (with no water) to check and make sure everything works (which is a traditional annual practice with no previous issues)...FP1 starts and runs, FP2 will not. In my troubleshooting, I moved FP2 over the the ATS48 to see if it would run and it did just fine. So...the ATS48 will run both motors under no load but the ATS46 will not. I have not yet tried FP1 with the ATS46...though I'm assuming I will have the same result. Is it worth trying to reprogram the ATS46 or do I just replace it with a new ATS48?

 

[ptonsparky]

Very Interesting and does make sense...let me throw this out at ya though. Here is the whole story. You are correct that the pump is not moving any water so the motor is indeed not loaded. There are two identical 230 volt 25 HP motors for Filter Pump #1 (FP1) and Filter Pump #2 (FP2). Both motors look to be the same age at approx 12 years old. The soft starts however, are not...FP1 drive has since been replaced with a Telemechanique Altistart 48 ATS48D88YU though I'm not sure when as it was before they started calling me. The staff tried to start them a couple of days ago (with no water) to check and make sure everything works (which is a traditional annual practice with no previous issues)...FP1 starts and runs, FP2 will not. In my troubleshooting, I moved FP2 over the the ATS48 to see if it would run and it did just fine. So...the ATS48 will run both motors under no load but the ATS46 will not. I have not yet tried FP1 with the ATS46...though I'm assuming I will have the same result. Is it worth trying to reprogram the ATS46 or do I just replace it with a new ATS48?

Speaking from the experience I gained today, you might want to check out the simple stuff first. Unless you can afford to have a spare SS sitting around.:slaphead:

 

[jerjwillelec]

Speaking from the experience I gained today, you might want to check out the simple stuff first. Unless you can afford to have a spare SS sitting around.:slaphead:

Ok...what am I missing here? :?

 

[texie]

9.9 times out of 10, this is the result of the load on the motor being too light.

Most soft starters on the market require that the current flowing through the current sensors inside of it be at least 20-30% of the rating of the unit (varies by mfr.). That's how they determine phase loss, because they do not actually measure voltage, only current. So if AT LEAST one phase current is below that threshold, it means you have a phase loss somewhere. But if ALL 3 phases are below that threshold, the condition is still true, so it ASSUMES this is a phase loss.

You have most likely:
A) not yet connected the motor,
B) left the motor disconnect switch open
C) left a valve closed somewhere so no water is flowing and since water flow = load on a pump, the motor is unloaded and not drawing enough current to satisfy the Phase Loss trip condition.
D) a SERIOUSLY clogged filter!

I almost guarantee it...

Jraef, thanks for a well reasoned and experienced reply. While I have a fair amount of miles on me in the trade, VFD's add a great deal of complexities that can only be dealt with by experience and sound engineering thought. I have learned a lot from your reply's over the years.

 

[ptonsparky]

Ok...what am I missing here? :?

I ended up owning a VFD I did not need because I did not check for simple problems/solutions first.

 

[kwired]

Ok...what am I missing here? :?

Check everything in Jraef's list for starters. Try running the one in question with water in the pump instead of running dry, that is one thing in the list.

 

[jerjwillelec]

I ended up owning a VFD I did not need because I did not check for simple problems/solutions first.

I guess I'm running out of simple problems to check for... :? The FP2 motor will run on the ATS48 so I know the motor is good. I'm going to see if FP1 (the other motor) will run on the ATS46 and add that result to what I already know. Using the information I have so far ie: the fact that one of the origional ATS46 drives have already been replaced previously and that the motor in question is good...I'm not sure what else I can to check...

 

[jerjwillelec]

Check everything in Jraef's list for starters. Try running the one in question with water in the pump instead of running dry, that is one thing in the list.

I'll check but I don't think filling the lines is an option until they fill the pool which is weeks out yet. Then, if I find out it is the drive, I wait another week for it to arrive to change it out.....

 

[Jraef]

Looks as though the thresholds are different for the two different versions:

If the motor current falls below this threshold in one phase for 0.5 s or in all three phases for 0.2 s,
the starter locks and displays the fault PHF.
Can be set at between 5 and 10% of the ICL starter rating.

ULL
Motor underload
threshold
(Level 2 only)
% 20 to 100 of measured
nominal motor torque

An underload threshold can be set to prevent damage to the
driven machinery or process resulting from an underload
condition (i.e., dry pump condition). The underload detection
is only active during steady state operation.
To prevent nuisance tripping, the underload condition must
last for 4 seconds. If a short underload condition occurs and
loading returns to a value 10% above the user-defined
threshold, the underload detection is reset.

So it appears as though the ATS46 is 20-100% of MOTOR CURRENT setting, the ATS48 is 5-10% of the UNIT rating.

 

[jim dungar]

Looks as though the thresholds are different for the two different versions:
So it appears as though the ATS46 is 20-100% of MOTOR CURRENT setting, the ATS48 is 5-10% of the UNIT rating.

Been there, done that.

Unlike some drives, the softstart really doesn't know there is a motor present until it is up to speed. Can you add some other loads?

 

[kwired]

I'll check but I don't think filling the lines is an option until they fill the pool which is weeks out yet. Then, if I find out it is the drive, I wait another week for it to arrive to change it out.....

Find some other way to put some load on the drive??

Just a thought, not sure but I think it would work, but maybe put some resistive load on the output along with the motor. Jraef?

 

[jerjwillelec]

Been there, done that.

Unlike some drives, the softstart really doesn't know there is a motor present until it is up to speed. Can you add some other loads?

Update... I hooked up FP1 (the other motor) up to the ATS46 (drive in question) and it will not start. For kicks, I hooked both motors up to the ATS46 (in hopes of adding more load to the drive) and I get the same result...PhF.

 

[jerjwillelec]

Find some other way to put some load on the drive??

Just a thought, not sure but I think it would work, but maybe put some resistive load on the output along with the motor. Jraef?

Interesting thought...the only resistive load I can come up with would be a three phase electric heater and I don't have access to one presently...

 

[kwired]

Interesting thought...the only resistive load I can come up with would be a three phase electric heater and I don't have access to one presently...

Three single phase loads connected in a Delta (or even a wye) would work also. Delta connected each individual load sees line to line voltage, connected in wye it sees about 58% (recriprocal of 1.73) of line to line voltage. So if line to line voltage was 208 then you could connect 120 volt heaters in a wye configuration - don't connect the mid point to anything.

 

[jerjwillelec]

Three single phase loads connected in a Delta (or even a wye) would work also. Delta connected each individual load sees line to line voltage, connected in wye it sees about 58% (recriprocal of 1.73) of line to line voltage. So if line to line voltage was 208 then you could connect 120 volt heaters in a wye configuration - don't connect the mid point to anything.

At the risk of sounding like an idiot...can you elaborate a little more on this...maybe consider me not as smart as you?

 

[kwired]

At the risk of sounding like an idiot...can you elaborate a little more on this...maybe consider me not as smart as you?

If this is 208 or 240 volts and you have three single phase heaters rated 240 volts just connect one between each output terminal (resulting in a delta configuration of the output loads). Total current at full voltage will be 240 (or 208) divided by 1.73.

If you have 120 volt heaters connect them in a wye configuration instead. One lead of each heater to an output lead of your starter and other leads all three tie together (the mid point of the wye) but do not ground this point. Each heater will see 120 volts if the input is 208, but will be higher if input is 240 - about 138 volts.

This is no different than connecting transformer or motor windings in same configurations.

 

[Jraef]

Find some other way to put some load on the drive??

Just a thought, not sure but I think it would work, but maybe put some resistive load on the output along with the motor. Jraef?

Yep, that's how we tested them at the factory. At one place I worked, we just put some immersion heaters into a barrel of rain water out in the back of the plant (we were in Florida, anything we could do to avoid heating the air indoors was helpful!).