How many AC amperes are there in DC amperes

You can say that the DC ampere value of current is equal to the root mean square value of an AC current of the same magnitude. The AC current changes its value from Positive Peak to Negative Peak in a cycle and the root mean square value or an Irms value is the Peak Value divided by Sqrt of 2 or = 1.414

So I peak = Irms / 1.4142

Hence whicle calculating DC amperage from AC amperage you have to consider the following terms :
AC Amperage
AC Volatage
Wattage
DC Voltage

You can use an online tool to convert this please follow the link : http://www.batterystuff.com/kb/tools/ac-to-dc-amperage-conversion-run-through-an-inverter.html

Can we get three phase supply from a single phase supply?

Yes we can get three phase supply from a single phase supply using a motor | alternator set or we can use a solid state inverter circuit to do this. There is a device abbreviated as VFD - Variable Frequency Device that can be used to convert the single phase supply to a 3 phase supply.
Here if we consider 3 phase motor as the load and it is connected to the output end of the three phase supply and the input end of the supply is connected to any two phase from the single phase output. There is an internal switch that is needed to be changed for the VFD to know that it should be considering only 2 lines on the output to be high.

A more clear explanation can be read here - http://www.answers.com/Q/How_do_you_convert_single_phase_supply_to_three_phase_for_running_a_3-phase_motor

How to calculate slip in Electrical Machines

It is common to express the slip as a ratio between shaft rotation speed and synchronous magnetic field speed. The Slip is often expressed as

    S = (ns - na) 100 / ns   %

synchronous speed at any given value of pole can be calculated us

Calculate Ns using - 120f / p    : where  f is the frequency and p is the number of given poles
Na is the Speed which is given ( shaft rotating speed (rev/min, rpm) )

If putting the above values give a -ve slip then it will act as a generator.

Do Capacitors work on DC ?

Here is a simple explanation :

There will be no current through a capacitor is the voltage across the ends is not changing with respect to time. 
So irrespective of the circuit whether its an AC or a DC if the voltage across the ends of a capacitor changes with time then there will be a current through it and hence there will be a change in the current in the external circuit  to which it is connected.

It is a Known fact that AC changes its polarity depending upon the supply frequency and hence there will be a change in the circuit current .

But in D.C there is no change in voltage across the capacitor normally. And hence there will be no change in the current in the external circuit .

I hope this explanation will help, if you feel its wrong please comment below. 

Creeping In Energy Meters

What is Creeping ? 

In some cases in the operation of energy meters, even when there is no load the disc rotates slowly and continuously this rotation of the disc without any current flowing through current coil and only due to excitation of pressure coil is called creeping

This is prevented by applying following measures: two diagrammatically opposite holes are drilled in the disc of energy meter and doing this cause sufficient distortion of the field. The result is that disc tends to remain stationary when one of the holes comes under one of the poles of the shunt magnet.