Tag Info

New answers tagged three-phase

1

Data centers use 3 phase because utilities will insist on it for the amount of power they use. If they were to give them single phase, it would cause a severe imbalance of the 3 phase utility transmission lines. Single phase service drops are generally limited to 167.5kVA (around 800A) maximum, most data centers use thousands of amps.

0

The real problem is that the stresses involved with achieving say 10% ripple voltage with split phase is that the charge current can only operate during 10% of the time so its decay period of 90% of the time is the actual discharge load current while the charge current is the load plus the charge current to reach diode peak voltage. this results in the ...

3

We were offered 120V or 208V at at one US data center, so three phase is available. Six pulse rectifiers are efficient at making DC, but powerful DC circuits are hard to manage once you exceed the working voltage of your typical arc welder. Ordinary switched mode power supplies start with rectifier followed by a a power-factor correction circuit, these will ...

4

The actual connector part will fit without problems - a 4mm banana connector always fits the same across all vendors. Unfortunately the plastic protection is not standardized - I experience problems every now and then. Either the plastic is too long or the thicker part of the connector starts too early or the tiny plastic cap in the middle of the banana plug ...

0

They're all the same 4mm diameter banana hole same diameter shroud and a compatible springy pin. For a phase sequence meter choosing plugs with a shroud that's deep enough to fully protect the pin is probably important.

2

The motor current rating indicates that the motor is not a 5 Hp motor by international standards. You should be looking for a 3 Hp VFD. There VFDs on the market at that power level that can provide the required output voltage and current with single-phase input power. There are models rated for 120 V, single-phase input and 230 V, three-phase output. You don'...

2

I definitely agree with Stainless steel Rat. I'm an Winder and work with Electric Motors for 4 years now. You'll get an open circuit between A&D if the motor heats up beyond 150°C most likely but that won't open the winding, the contactor or starter will kick the overload. But to be 100% sure if you post a pic of the winding I can definitely tell you if ...

6

It certainly appears to be a three-phase induction motor. The resistances between leads B, C and E seems high for stator resistance, but the fact that they are equal would indicate they are U, V and W. Which is which doesn't matter much. If the motor runs backwards when powered, swap two of them. The resistance between A and D would be nearly zero if it is ...

6

You have a three phase motor with thermal protection. From True Fitness Max Drive Motor AC 5 HP CS6.0 CS8.0 OC460000 Works with Treadmill by True Fitness. So if you look at your results. A is only connected to D. This corresponds to P1 and P2 Thermostat leads. BC = 2.2 CE = 2.5 BE = 2.5 These correspond to UVW (Line 1 to 3). The order does not mater, ...

1

A-D thermal trip, goes open circuit when internal winding temperature goes too high(usually 80-105C) B,C,E 3 phase supply Above assumes you are in 110v/60Hz country. When connected correctly motor should spin clockwise when looking from the back, swap any 2 phases if going backwards.

0

Because what's important are the currents not the voltages. You do adjust current by voltage control. The current VS. voltage has a phase delay. You do have a current setpoint and measured current, you do adjust PWM duty cycle to bring up voltage so that the setpoint current will flow through motor winding. simulate this circuit – Schematic created ...

0

First, realize these observations: Applying Ohm's law to the resistor in phase a: $v_\text{an} = R \, i_\text{a}$. So, if $i_\text{a} = 0$ at some instant, then $v_\text{an} = 0 \, R = 0$ too. And if $i_\text{a} \ne 0$, then $v_\text{an} \ne 0$. Only one SCR of each parallel group (1 and 4; 3 and 6; 5 and 2) can conduct at a given ...

Top 50 recent answers are included