Do any of you have experience in the installation of multiple hydraulic injection molding machines? The pump motors experience a spike during the cycle that may be twice the FLA or more but is very short in duration. I need to establish a demand factor that can be applied to my load calculations.
Injection molding machines
- Thread starter alwinj
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- Massachusetts
I would think that if the circuit can start the motor (Locked rotor 6 to 8 times FLA) it should be able to handle 2 x FLA.
IMM_Doctor
Senior Member
Multiple IMM's
Multiple IMM's
When sizing a circuit to an individual Injection Molding Machine:
FLA of Largest motor x 125%
plus the sum of the FLA's of the remainder of the motors
plus Total Electric Heat Load Amps x 1.25
Yes it is common for a machine to have various KW demand throughout an individual machine cycle. When connecting multiple machines, the feeder will see the "average" load of all of the machine's. The more accurate information you gather up-front will allow you to install an economic and adequate feeder to multiple machines.
You can put a single channel DMM with averaging function on one-phase of the incoming line and record the average over several machine cycles.
This would be the minimum effort, and may yield some insightfull infomation. Such as minimum calculated feeder to inividual machine = 600 amps, yet the average amperage over several cycles = 150 amps.
Therefore, you still need a 600 amp circuit to the individual machine.
But your choices for the feeder to (6) machines falls somewhere between
6 x 600 = 3,600a
or
6 x 150 = 900a.
You can also apply 3-ph 4w power recording equipment to the feeder to the machine to gather a more detailed load study which will give you actual kw and power factors. Power factor is at it's worst when the machines motors are running, and not loaded.
You can not gather this information on one type of machine, IE a 500 Ton Van Dorn, and assume a 500 Ton Milacron will be the same.
Also WATCH out for auxilliary equipment. Sometimes the machines have been modified and auxilliary equipment outlets have been added to the machine it self.
Lastly, be aware that the kw demand of the machine varies depending the the molding process itself. If you collect information on a particualar process that is an easy material to inject, and has a long cooling time, your numbers will be low. If the customer changes the tool with a harder plastic material to inject and extrude, and has shorter cooling time requirements, the numbers will go up. Ask the customer about the various tools that are intended to run in the machine.
Multiple IMM's
alwinj said:
When sizing a circuit to an individual Injection Molding Machine:
FLA of Largest motor x 125%
plus the sum of the FLA's of the remainder of the motors
plus Total Electric Heat Load Amps x 1.25
Yes it is common for a machine to have various KW demand throughout an individual machine cycle. When connecting multiple machines, the feeder will see the "average" load of all of the machine's. The more accurate information you gather up-front will allow you to install an economic and adequate feeder to multiple machines.
You can put a single channel DMM with averaging function on one-phase of the incoming line and record the average over several machine cycles.
This would be the minimum effort, and may yield some insightfull infomation. Such as minimum calculated feeder to inividual machine = 600 amps, yet the average amperage over several cycles = 150 amps.
Therefore, you still need a 600 amp circuit to the individual machine.
But your choices for the feeder to (6) machines falls somewhere between
6 x 600 = 3,600a
or
6 x 150 = 900a.
You can also apply 3-ph 4w power recording equipment to the feeder to the machine to gather a more detailed load study which will give you actual kw and power factors. Power factor is at it's worst when the machines motors are running, and not loaded.
You can not gather this information on one type of machine, IE a 500 Ton Van Dorn, and assume a 500 Ton Milacron will be the same.
Also WATCH out for auxilliary equipment. Sometimes the machines have been modified and auxilliary equipment outlets have been added to the machine it self.
Lastly, be aware that the kw demand of the machine varies depending the the molding process itself. If you collect information on a particualar process that is an easy material to inject, and has a long cooling time, your numbers will be low. If the customer changes the tool with a harder plastic material to inject and extrude, and has shorter cooling time requirements, the numbers will go up. Ask the customer about the various tools that are intended to run in the machine.
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