I = P/(V x Cos pi) Amps KW = output power in Watts All of this information may be found on the motor's nameplate. It is important to understand that these are maximum values that can be used as a guide only when data for different motors are compared side by side. Motors with higher load currents will require more powerful drivers/controllers.
The load current determines how much electrical energy will be consumed by the motor at any given time. The average load current determines the average power consumption of the motor. The load current also affects the life of the motor; higher load currents mean greater wear and tear on the motor components. As well, high load currents may cause overheating which could lead to burning out parts of the motor.
The load current depends on how fast you drive the motor and what type of load it is driving. If the driver drives the motor at a constant speed but the load varies greatly, then the system will need to change direction often (which will increase the load current). This is called "directional loading". If the load is constant, then it won't matter if the driver runs forward or backward - both situations result in the same motor torque and power consumption. A motor used in this fashion is said to have "balanced loading".
In the tables below, find the typical motor kW to full load rate current in Amp conversion value at 0.86 pf. No. S. A. E. D. F. G. H. I. J. K. L. M. N. O. P. Q. R. S. T. U. V. W. X. Y. Z.
Use these tables to find the required voltage for a given load and speed. For example, to find the voltage needed to run at 100% duty cycle at 690 rpm, use this formula: 100% DC = 120 V/[(3.6 x 1000) + (0.12 x 690)] = 119.8 V.
Here are some other examples: If you want to run at 90% DC and 720 rpm, then the required voltage is 117.6 V. If you want to run at 80% DC and 900 rpm, then the required voltage is 116 V. At any speed between 50% DC and 1200 RPM, the required voltage is equal to the sum of 2 times the no-load voltage plus 30 percent of the no-load voltage over 750 rpm.
The motor full load current calculator computes the motor full load current based on the following inputs: The voltage (V). A 3-phase supply's phase-to-phase voltage or a single-phase supply's phase-to-neutral voltage. Phase. Regardless of whether the power supply is three-phase or single-phase, it must be connected to the motor properly for the calculator to function. If any part of the circuit is not complete, such as no third wire is attached to some phases, then the calculator cannot determine the correct motor loading and will not calculate correct values.
There are two ways to compute the full load current of a motor: The first method uses only one voltage value, which represents the average of the three phases if the power supply is three-phase or just one phase if it's single-phase. In this case, the motor full load current is calculated by multiplying the voltage by the motor's winding resistance.
The second method uses three different voltage values, which represent the individual phases of a three-phase power supply or the neutral-to-ground voltage of a single-phase power supply. In this case, the full load current is calculated by multiplying the voltage by the motor's winding resistance plus the two other resistors required by the particular calculation method used. These additional resistors may have their value written as "AR" or "XAR".
When the actual load current equals the motor's full load current rating, the starting current may be calculated as FLA x 7.5./span > Istart.
Where: FLA is the full load amps rating of the motor (6 for a 6-volt system or 12 for a 12-volt system). Istart is the starting current in amperes.
For example, if you have a 4-horsepower motor that draws 1.8 amps at startup, the starting current would be (1.8 x 7.5 = 13.4), so the calculation would be 4 = FLA x 7.5/13.4.
Keep in mind that this is only true when the motor is running and not when it's first started up. After it has run for a while, the current consumption will drop off significantly until it reaches its normal operating point.
The maximum load current is the minimum amount of current in amps that must be drawn from a certain output in order for it to function. The maximum load current determines the size of the power supply's transformer and its cost. In general, the larger the maximum load current, the bigger the power supply can be used without causing problems due to heat.
There are two types of limits: peak and continuous. The peak load current is the highest amount of current drawn from the supply in any short period of time. For example, if you were to measure the peak current with an ammeter during use, you would find out how much stress the supply is under at any given moment. This is important because excessive peak currents may cause overheating and failure of the component.
The continuous load current is the average amount of current consumed by the device over a long period of time. It is calculated by dividing the total amount of current used by the battery charger over time by time. For example, if you charged a battery with a charger that kept track of the current used and it took two hours to charge the battery down to zero, then the continuous load current would be 0.5 amp.
Full-load current (FLC) is the current value shown in Tables 450.247–450.250. The motor's actual current drawn is determined by the driving load and the operating voltage at the motor terminals. When the load grows, so does the current. A motor will usually draw less current when running at high speed, because there is less demand for torque.
Table 450-24 lists some common full loads for motors from 1/4 horsepower (750 watts) to 15 horsepower (10 kilowatts). Use these numbers as a guide only; depending on how you connect your motor up, it may not get a full load all of the time. For example, if you run a fan continuously with no load, it will still draw current from the battery even though nothing is using any energy from the motor.
As long as your motor is getting enough current to run properly, the type of load it carries is not important. If you want to use a low-current device such as a light bulb or radio instead of a pump, motor, or air conditioner, that's fine. The key thing is that it not cause the motor to run too fast or burn out prematurely due to overloading.
The FLC value given in Table 450-24 is the maximum current draw that the motor can handle indefinitely. In practice, motors often operate well below their FLC rating.