Answer / s.karthik

greater voltage if applied for greater period of time will
lead to insulation failure of the windings,coz of which the
windings will get short circuited,huge amount of current
will flow and as a result the motor will burn

Answer / roysayan01

Firstly the brushes and commutator will simply burn out
because of the high current. Secondly insulation depends on
rated voltage and if double the rated voltage is applied
insulation failure will take place.

Answer / solanki

I think that if we apply the twice voltage across the dc
moter then it will take large current bcz armature current
depend upon the as
I =v-(back emf)/armature resistance
simply if we increses voltage then current will increses
also then more heating & can damage to winding of moter

Answer / venkatesh

Always Voltage will depending on insulation & current will depending on core of wire.similarly the winding wire (copper wire) also Manufacturing in same manner if voltage will rise twice then the rated voltage the insulation will burn and shorted to anther winding turns Due to this whole motor winding will burn.

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Dear all, I just want to ask an expert on this forum for some insights. For the magnetic balance test, when applied voltage on a Delta-Star transformer e.g. Dyn11, the following relationships apply for HV side: 1.  H1-H2 = H2-H3 H3-H1 2.  H2-H3 = H3-H1 H1-H2 3.  H3-H1 = H1-H2 H2-H3 For the LV side also: 4.  X1-X0 = X2-X0 X3-X0 5.  X2-X0 = X3-X0 X1-X0 6.  X3-X0 = X1-X0 X2-X0 Is there a similar pattern for Y-d, Y-Y, D-d? And how about Y-z, D-z, Z-y transformers? I've tested a YNzn5 transformer and for LV side I don't see the pattern. In this particular case I got for LV side the following (see values below): H1-H0  H2-H0  H3-H0    X0-X1  X0-X2  X0-X3 128.0  119.9  7.2      29.2   13.3   15.8 70.7   128.4  59.2     23.4   22.0   3.6 7.2    120.1  128.1    13.4   29.3   15.8 What is the relationship here for LV? For row 1 I see the relationship, for row 3 I also see but it's shifted, but for row 2 I don't see such relationship. Any suggestions, answers, someone?

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