New ACRA 1440C lathe with Mark Jacobs VFD

[SD Crane man]

Technically for single phase input the GA50UB018AB is a better rated VFD looking at the output amps. To some degree it comes down to your motor amps. The GA50U2030ABA should work well, but probably would benefit from a DC choke (25A-32A). In my lathe with a 3 Hp motor I run a Yaskawa V1000 3 phase CIMR-VU2A0020FAA VFD which has an output of 19.6A and in derated mode for single phase input it is rated at~11.5A, with a 18A DC buss choke, and it can be run off of single or 3 phase. My motor pulls 8.3A, so I have plenty of headroom, which is not the case with the GA50U2030ABA and a 5 Hp motor pulling 14 or more Amps. It will work, since you rarely pull full motor amps, but I would probably us a DC choke and/or dial down the overload point to 130% instead of 150%. MTE makes DC buss chokes (DCA002504, DCA002504, DCA003201, DCA003202) that are readily available, but additional cost and space in the VFD cabinet.

MTE DCA003201 DC Link Choke 0.85mH, 32ADC, 1000VDC MAX - NEW | eBay

These services include NO VERBAL CONFIRMATION WILL BE GIVEN, THIS MUST BE IN WRITING. Item is sold as pictured.

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Mark,
At the risk of beating a dead horse to a shapeless pulp.
These are the GA50U2030ABA specs. I have read that to derate the VFD you use vfd output amp/1.73. What I don't understand is which of the two ratings below are used? 25, or 30? If I'm understanding this correctly and the 25 amp rating is what would be used that leaves me with 14.45 amps available. The motor tag shows the motor draw at 230 volts is 14 amps That sure wouldn't leave much headroom. I understand the lathe would probably never work that hard, but with the lotteries I tend to win I would be concerned about the motor running hot.
Thoughts?


Item Number:
GA50U2030ABA
Brand:
Yaskawa
Item Category:
Drives
Subcategory:
AC
Series:
GA500
Input Range VAC:
200 to 240 Volts AC
Input Phase:
3
HP (CT):
7.5 Horsepower
Amps (CT):
25 Amps
HP (VT):
10 Horsepower
Amps (VT):
30 Amps
Max. Frequency:
590 Hertz
Braking Type:
DC Injection;Dynamic Braking
AC Line Regenerative:
No
Closed Loop:
No
Motor Control-Max Level:
Open Loop Vector (Sensorless Vector)
Operator Controls:
Keypad Included
IP Rating:
IP20
Comments:
Side-By -Side Mounting, Includes Safe Torque Off, Setup Wizard For Easy Start-up, LED Status Ring
Mounting:
PANEL
Frame Size:
5
Refurbished:
New
H x W x D:
10.24 in x 5.51 in x 5.51 in
Net Weight:
7 lb 8 oz

 

[mksj]

When looking at a VFD for lathes I usually run them in the maximum duty condition, typically the default is 150% overload, vector motors I go to 180%. So you need to look at the VFD output current rating for constant torque and usually this is listed as HD mode, or others ND in constant torque mode.

These days VFD's have a wide range of "Hp" and "Output Amp" ratings and also derating factors, my understanding according to others in the industry this is because they are being built to lighter duty specs. You also need to take into account the specific manufacturer specification of the model and the derating conditions that the manufacture states as to thing like ambient temp., carrier freq., enclosure volume, etc. Yaskawa does specify a derating factor of ~1.7 for single phase, they also specify that this is with using a DC choke. The DC choke decreases the current draw pulses and also the input fusing requirements, so in general a good idea if using a 3 phase VFD in derated mode. W/O a choke the industry standard is more like a factor of 2 for derating. Newer VFD's from Automation Direct (GS20) have a derating of 2-3, and this also applies to the newer Hitachi line of the SJ-P1 series. So for the motor you have outlined you would need to use their VFD rated for 11kW 46A which in derated mode is rated at 13.3 to 15.5A. Please not that derating is based on industrial use with running the VFD continuously at close to maximum output, so yes you could get by with a lesser derating or model that just meets specs. So the GA50U2030ABA with a DC choke would be adequate, and Yaskawa VFD's tends to be very durable and rated for 24/7 use for many years.

Hitachi SJ-P1 VFDs

 

[SD Crane man]

When looking at a VFD for lathes I usually run them in the maximum duty condition, typically the default is 150% overload, vector motors I go to 180%. So you need to look at the VFD output current rating for constant torque and usually this is listed as HD mode, or others ND in constant torque mode.

These days VFD's have a wide range of "Hp" and "Output Amp" ratings and also derating factors, my understanding according to others in the industry this is because they are being built to lighter duty specs. You also need to take into account the specific manufacturer specification of the model and the derating conditions that the manufacture states as to thing like ambient temp., carrier freq., enclosure volume, etc. Yaskawa does specify a derating factor of ~1.7 for single phase, they also specify that this is with using a DC choke. The DC choke decreases the current draw pulses and also the input fusing requirements, so in general a good idea if using a 3 phase VFD in derated mode. W/O a choke the industry standard is more like a factor of 2 for derating. Newer VFD's from Automation Direct (GS20) have a derating of 2-3, and this also applies to the newer Hitachi line of the SJ-P1 series. So for the motor you have outlined you would need to use their VFD rated for 11kW 46A which in derated mode is rated at 13.3 to 15.5A. Please not that derating is based on industrial use with running the VFD continuously at close to maximum output, so yes you could get by with a lesser derating or model that just meets specs. So the GA50U2030ABA with a DC choke would be adequate, and Yaskawa VFD's tends to be very durable and rated for 24/7 use for many years.

Hitachi SJ-P1 VFDs
View attachment 402467Thanks againMark.

As it turns out the 50UBO18ABA isn't available. The supplier I was talking to contacted Yaskawa. He was told it would be 4-6 weeks, but it could be up tp six months to get it. One of the other things I will need to address are control relays. The machine still has the contractors in it. What is a good reliable relay for this purpose?
Thank you.
George