function isNumeric(pccharinput) {  
	return(pccharinput>="0" && pccharinput<="9")
}

function ischeckPhase(pccharinput) {  
	return(pccharinput=="1" || pccharinput=="2" || pccharinput=="3")
}




function checkKVA1() {
if (!isNumeric(document.form.kva.value)) {
	alert("Please enter a valid number");
	document.form.kva.focus();
	document.form.kva.select();
	return false;
	}
}

function checkKVA3() {
if (!isNumeric(document.form.volts.value)) {
	alert("Please enter a valid number");
	document.form.volts.focus();
	document.form.volts.select();
	return false;
	}
}

function checkPhase1() {
if (!ischeckPhase(document.form.phase.value)) {
	alert("Please enter a number between 1 and 3");
	document.form.phase.focus();
	document.form.phase.select();
	return false;
	}
}

function checkKVA2() {
if (!isNumeric(document.form2.kva.value)) {
	alert("Please enter a valid number");
	document.form2.kva.focus();
	document.form2.kva.select();
	return false;
	}
}

function checkKVA4() {
if (!isNumeric(document.form3.kw.value)) {
	alert("Please enter a valid number");
	document.form3.kw.focus();
	document.form3.kw.select();
	return false;
	}
}

function checkKVA5() {
if (!isNumeric(document.form4.kw.value)) {
	alert("Please enter a valid number");
	document.form4.kw.focus();
	document.form4.kw.select();
	return false;
	}
}

function checkKVA6() {
if (!isNumeric(document.form5.hp.value)) {
	alert("Please enter a valid number");
	document.form5.hp.focus();
	document.form5.hp.select();
	return false;
	}
}


function CalcKVA(form,volts,kva,phase) { 
	var V = parseInt(volts); 
	var K = parseInt(kva); 
	var P = parseInt(phase);
	var A = 0; 

	if (P == 1) {
		A = ((K * 1000)/V); 	
	}
		else if (P == 2 || P == 4)  {
		A = ((K * 1000)/(2*V)); 	
	}
		else if (P == 3) {
		A = ((K * 1000)/(1.73*V)); 	
	}
	return(A); 
} 

function calulate(form) { 
	if ((form.volts.value == null || form.volts.value.length == 0)) { 
	return; 
	} 

	var V = form.volts.value; 
	var K = form.kva.value; 
	var P = form.phase.value;
	var A = 0;
	
	A = CalcKVA(form, V, K, P); 
	form.Ampere.value = A; 
	
	return; 
} 

function calculateKVA2KW(form) {
	if ((form.kva.value == null || form.kva.value == 0)) {
	return;
	}

	var K = form.kva.value;
	var W = 0;
	W = K * 0.8;
	form.kw.value = W;
	return;
}

function calculateKW2KVA(form) {
	if ((form.kw.value == null || form.kw.value == 0)) {
	return;
	}
	var W = form.kw.value;
	var K = 0;

	K = W / 0.8;
	form.kva.value = K;
	return;
}

function calculateKW2HP(form) {
	if ((form.kw.value == null || form.kw.value == 0)) {
		return;
	}

	var W = form.kw.value;
	var H = 0;

	H = W / 0.746;
	form.hp.value = H;
	return;
}

function calculateHP2KVA(form) {
	if ((form.hp.value == null || form.hp.value == 0))	{
	return;
	}

	var H = form.hp.value;
	var K = 0;
	var S = 1;
	var R = 1;

	if (H < 50) {
		R = 1.5;
	}
	else if (H > 49 && H < 100) {
		R = 1.4;
	}
	
	else if (H > 99) {
	R = 1.3;
	S = 5;
	}
	
	if (H < 30) {
	S = 7;
	
	}
	
	else if (H > 29 && H < 100) {
		S = 6
	}

	K = ((H * R * S) / 2) / 1.39;    

	form.kvarequired.value = K;
	return;
}