Flickering of lights and vibrating of freezer compressors
In all likelihood the alternator is not putting out the type of AC waveform that the appliances expect. Depending on your location the AC mains from the utility service will be a single frequency sine wave of 50Hz or 60Hz. An alternator will often put out a three phased AC signal that will vary in frequency depending upon the RPM of your diesel engine.

Also since alternators are typically used in applications where the output is rectified and then used to charge a battery in a DC circuit the frequency based upon engine RPM is not of a concern for those applications. 

Of course there are loads you can put on the rectified output of an alternator that will work OK as long as the voltage is the correct level. Incandescent lighting would fit this usage but if you have certain typed of florescent lights or AC line powered LED lights they are not going to like operating outside of their 50/60Hz frequency range with the proper AC sine wave voltage level.