SPX Cooling Technologies TG MAG58-80 Sound power level LWA, where, the highest sound level

The values depend on the position from where one measures and were therefore measured at the front of the pump, at distance of 1 meter from the pump cover and were corrected for background noise and reflections.

The values listed are the highest measured values under following operating conditions.

•working pressure: up to 10 bar.

•pumped medium: water, viscosity = 1 mPa.s

•—% nmax = — % maximum shaft speed

			Lpa (dB(A))
TG MAG pump size	nmax(min-1)					Ls (dB(A))
		25% nmax	50%nmax	75%nmax	100%nmax
15-50	1500	61	72	79	83	9
23-65	1500	63	75	81	85	10
58-80	1050	67	79	85	89	10
86-100	960	69	80	86	90	11
185-125	750	71	82	87	91	11

Sound power level (LWA)

The sound power LW is the power emitted by the pump as sound waves and is used to compare sound levels of machines. It is the sound pressure Lp that acts on a surrounding surface at distance of 1 meter.

LWA = LpA + Ls

The A-weighted sound power level LWA is also expressed in decibels dB(A).

The reference sound power is 1 pW (= 10-12W). LS is the logarithm of the surrounding surface at distance of 1 metre from the pump, expressed in dB(A) and is listed in the last column of the table above.

3.7.2The sound level of the pump unit

The sound level of the drive (motor, transmission,…) must be added to the sound level of the pump itself to determine the total sound level of the pump unit. The sum of several sound levels must be calculated logarithmically.

For a quick determination of the total sound level the following table can be used:

L1–L2	0	1	2	3	4	5	6
L[f(L1–L2)]	3.0	2.5	2.0	1.7	1.4	1.2	1.0
Ltotal = L1 + L corrected
where		Ltotal		: the total sound level of the pump unit
		L1		: the highest sound level
		L2		: the lowest sound level
		Lcorrected		: term, depending on the difference between both sound levels

For more than two values this method can be repeated.

Example:	Drive unit	: L1	= 79 dB(A)
	Pump	: L2	= 75 dB(A)
	Correction	: L1	- L2 = 4 dB(A)
	According to the table	: Lcorrected = 1.4 dB(A)

Ltotal = 79 + 1.4 = 80.4 dB(A)

A.0500.551 – IM-TGMAG/02.00 EN (02/2008) 17