On the boiler plate of a turbo charger (Type seems to be TPS57-F32, probably an ABB model, but manufacturer is not displayed) I found the following temperatures:

$$ t_{M_{max}} = 650°C $$ $$ t_{B_{max}} = 620°C $$

Obviously these temperatures are limits for temperatures at the turbine side. But what do they mean in particular?

  • $\begingroup$ 2 turbines - one in the hot ie exhaust stream one in the inlet stream. $\endgroup$
    – Solar Mike
    Commented Nov 16, 2022 at 8:25
  • $\begingroup$ @SolarMike I'm pretty sure this turbocharger has only one turbine and one compressor. And in case the second turbine you mentioned was meant to be a compressor, I think such a temperature at the inlet will ruin the CAC or even the motor. Typically temperatures before CAC are not exceeding 100°C. So this must be something different. $\endgroup$
    – Ariser
    Commented Nov 17, 2022 at 1:08
  • $\begingroup$ As you are sure then fine. $\endgroup$
    – Solar Mike
    Commented Nov 17, 2022 at 4:45

1 Answer 1


From ABB Operation Manual TPS57-F32

Operation above the indicated values $n_{B_{max}}$, $t_{B_{max}}$ can considerably shorten the recommended replacement intervals. In such cases, we recommend that you contact the nearest official ABB Turbocharging service station.

$n_{M_{max}}$ and $t_{M_{max}}$ normally apply only when running at overload (110%) during trials on the engine test bed. These limits can also be permitted during operation for special applications. Operation above $n_{M_{max}}$ and $t_{M_{max}}$ is not permitted.

$B_{max}$ is normal, not to be exceeded, operational limits, while $M_{max}$ are 110% one time, not to be exceeded, commisioning limits for the turbocharger (TC). As in: is everything working correctly if the TC is subjected to 110% of full-load.

From MAN B&W S90ME-C8-TII 2-stroke Diesel Engine.

Minimum delivery test

The minimum delivery test, EoD: 4 14 001, involves: • Starting and manoeuvring test at no load • Load test Engine to be started and run up to 50% of Specified MCR (M) in 1 hour

Followed by: • 0.50 hour running at 25% of specified MCR • 0.50 hour running at 50% of specified MCR • 0.50 hour running at 75% of specified MCR • 1.00 hour running at 100% of specified MCR • 0.50 hour running at 110% of specified MCR

During the commisioning process for large marine diesels, the diesel is run at 110% of Manufacturers Continuous Rating (MCR) for 30 minutes. The diesel and it's components can be measured to ensure ratings stabalize below specific maximums. In the case of the TC, ABB states that frequency and temperature should be below these $M_{max}$ limits ($t_{M_{max}} = 650°C$).

Similarily, normal operation limits $B_{max}$ allow periodic testing.

Both are easy to verify if written on the device.

  • $\begingroup$ Decent and elaborate explantaion! $\endgroup$
    – Ariser
    Commented Nov 20, 2022 at 0:41

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