Delta Electronics VFD007S23A manual Capacity Formulas, When one AC motor drive operates one motor

Appendix D CEVFD-S Series

C.1 Capacity Formulas

1. When one AC motor drive operates one motor

The starting capacity should be less than 1.5x rated capacity of AC motor drive

The starting capacity is

k ⋅ N	⎛	GD	2
	⎜
	⎜TL +	375
973 ⋅η ⋅ cos ϕ ⎝

N ⎞

⋅⎟ ≤ 1.5 ⋅ the _ capacity _ of _ AC _ motor _ drive(kVA) tA ⎟⎠

2.When one AC motor drive operates more than one motor

2.1The starting capacity should be less than the rated capacity of the AC motor drive Acceleration time ≦60 seconds

The starting capacity is

k ⋅ N			⎡		ns			⎤
		[nT + ns(ks − 1)] = PC1⎢⎢1		+		(ks − 1)⎥⎥			≤ 1.5 ⋅ the _ capacity _ of _ AC _ motor _ drive(kVA)
η ⋅ cosϕ					nT
			⎣					⎦
			⎢					⎥
		Acceleration time ≧60 seconds
	The starting capacity is
	k ⋅ N			⎡			ns		⎤
			[nT + ns(ks − 1)] = PC1⎢⎢1 +					(ks − 1)⎥⎥		≤ the _ capacity _ of _ AC _ motor _ drive(kVA)
η ⋅ cosϕ							nT
				⎣					⎦
				⎢					⎥

2.2 The current should be less than the rated current of the AC motor drive(A)

Acceleration time ≦60 seconds

+	⎡	+ n		⎜	−	⎟	⎤	≤	⋅
			S	⎛		⎞			1.5 the _ rated _ current _ of _ AC _ motor _ drive( A)
nT IM ⎢1			nT	⎝ kS	1⎠		⎥
	⎣						⎦
Acceleration time ≧60 seconds
	⎡	nS ⎛		⎞⎤		≤ the _ rated _ current _ of _ AC _ motor _ drive( A)
nT + IM ⎢1+			⎜ kS −1⎟⎥
	⎣	nT ⎝		⎠⎦

C-2 Revision August 2006, SE08, SW V2.61