Fred Raud
Member
tonight i was called on an inverter that kept faulting on overcurrent (F18,,TBwoods Etrac inverter 4001),,what was happening was after the inverter is a starter,,and the operator basically operated the starter,,
for a little background,,yesterday the inverter blew up, due to a bad motor,,so was replaced,,and not all of its parameters were reset,,
now theres a conveyor next to it and for all purposes in this thread can be considered its twin,,same 56c type motor,,same 1hp,,same 480v,,(supposed to be same gearbox,but as we are about to find out looks to not be the case),,so i used that one as a guideline to set the parameters of the one that blew being we had no back up or hard copy of that inverter,,
so,,all to gether,,set it to run at 17hz,,and most of the regular parameters set the same,,and fired up fine,,but ran really really slow,,so increased the frequency to 60hz to get it to the same speed as its 'twin',,figuring that somewhere along the ways the gear box got switched out with one we had and they used theinverter to match them up,,(no sprockets or chains to change ratio),,
figured all was ok,,but noticed that when we stopped the starter,,the inverter wasnt 'notified' so when we would push start,,the inverter would fault on overcurrent F18,,looking through the book and comparing the inverters parameters i noticed parameter 82(actually that was pointed out by my boss) was set at 0,,and should be set at 1 so as the inverter would ramp it up as it should,,well,since today rolled around,,i figured on their break id change the parameter,,and did such,,and it still had the same problem,,the only other parameter that i noticed different was 68(fault reset times,,basically the number of times within a 10 minute period the inverter would restart on its own if faulted,,i set it to 3 as its twin was set),
while they were on break,,i got curious and set the inverter to 17hz as its twin is,,started it,,and then started the starter,,and no fault,,so,,i put it back to 60hz,,and on starting would fault on overcurrent,,this is where my question lies,,
at 17hz,,thats roughly 25% of the frequency used to drive the conveyor with the problem,,so i am assuming the pwm is putting out a voltage of around 25% as well,,so around 120vac??and that would put the current draw 4x as much???if so,,wouldnt go to say that the motor running at 17hz shoujld be the one pulling the fault??or is my logic all messed up here?now,,i did do a current draw check on the motor while it was at 60hz,,was around .80amps,,,and i regretfully didnt do it at 17hz while i was at work tonight,,
also,,all things being the same,,frequency,,conveyor drive sprockets,,(they sit side by side,,and feed the same spiral cooler),,motor speed,,motor voltage,,motor hp,,inverter type,,and the only unknown is the gearbox(no data plate and didnt want to pull the motor to manually figure gear ratio),,is it safe to assume that the gear box ratio is the reason one inverter is set at 17hz,,and the other at 60hz to run at the same speed,,
and,,anybody familiar with etracs,,know if there is a way to have the inverter not have this problem when started from the starter without wiring it to the contactor or the start switch?i was told parameter 82 would do it,,(id define the parameter for those not familiar with etracs but dont have the book infront of me,,),
i think that about covers it for now,,
Fred Raud
for a little background,,yesterday the inverter blew up, due to a bad motor,,so was replaced,,and not all of its parameters were reset,,
now theres a conveyor next to it and for all purposes in this thread can be considered its twin,,same 56c type motor,,same 1hp,,same 480v,,(supposed to be same gearbox,but as we are about to find out looks to not be the case),,so i used that one as a guideline to set the parameters of the one that blew being we had no back up or hard copy of that inverter,,
so,,all to gether,,set it to run at 17hz,,and most of the regular parameters set the same,,and fired up fine,,but ran really really slow,,so increased the frequency to 60hz to get it to the same speed as its 'twin',,figuring that somewhere along the ways the gear box got switched out with one we had and they used theinverter to match them up,,(no sprockets or chains to change ratio),,
figured all was ok,,but noticed that when we stopped the starter,,the inverter wasnt 'notified' so when we would push start,,the inverter would fault on overcurrent F18,,looking through the book and comparing the inverters parameters i noticed parameter 82(actually that was pointed out by my boss) was set at 0,,and should be set at 1 so as the inverter would ramp it up as it should,,well,since today rolled around,,i figured on their break id change the parameter,,and did such,,and it still had the same problem,,the only other parameter that i noticed different was 68(fault reset times,,basically the number of times within a 10 minute period the inverter would restart on its own if faulted,,i set it to 3 as its twin was set),
while they were on break,,i got curious and set the inverter to 17hz as its twin is,,started it,,and then started the starter,,and no fault,,so,,i put it back to 60hz,,and on starting would fault on overcurrent,,this is where my question lies,,
at 17hz,,thats roughly 25% of the frequency used to drive the conveyor with the problem,,so i am assuming the pwm is putting out a voltage of around 25% as well,,so around 120vac??and that would put the current draw 4x as much???if so,,wouldnt go to say that the motor running at 17hz shoujld be the one pulling the fault??or is my logic all messed up here?now,,i did do a current draw check on the motor while it was at 60hz,,was around .80amps,,,and i regretfully didnt do it at 17hz while i was at work tonight,,
also,,all things being the same,,frequency,,conveyor drive sprockets,,(they sit side by side,,and feed the same spiral cooler),,motor speed,,motor voltage,,motor hp,,inverter type,,and the only unknown is the gearbox(no data plate and didnt want to pull the motor to manually figure gear ratio),,is it safe to assume that the gear box ratio is the reason one inverter is set at 17hz,,and the other at 60hz to run at the same speed,,
and,,anybody familiar with etracs,,know if there is a way to have the inverter not have this problem when started from the starter without wiring it to the contactor or the start switch?i was told parameter 82 would do it,,(id define the parameter for those not familiar with etracs but dont have the book infront of me,,),
i think that about covers it for now,,
Fred Raud